# CVE-2026-126073: Action Pack: Possible cache poisoning in Action Pack content negotiation

Status: published. Published: 2026-11-10. Updated: 2026-11-12.

Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, Action Pack negotiates the format of a rendered response from the Accept, X-Requested-With and, for XHR requests without Accept, Content-Type request headers, but ActionController::Rendering#_set_vary_header adds Vary: Accept only when the request carries a usable Accept header and the response has no Vary header yet. A response to a request without Accept, or to an XHR request, therefore omits the headers that selected its representation, and a response whose Vary the application set before rendering (for example Vary: Accept-Language) never gains Accept. A shared cache that honours Vary could store such a response and serve it to later clients that request a different representation, possibly leading to cache poisoning in which visitors receive, until the entry expires, a page without its layout or HTML in place of JSON. The attacker cannot choose the content of the response. Applications that render negotiated responses from actions marked public (for example with expires_in ..., public: true) behind a shared cache that honours Vary, such as Thruster or Rack::Cache, are affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

## Remediation

- fix: actionpack (RubyGems): OSV reports a fixed version 8.1.4.1. Check the advisory for supported release branches. (source: OSV GHSA-r9jg-fmfx-2gv6) — https://github.com/advisories/GHSA-r9jg-fmfx-2gv6
- fix: actionpack (RubyGems): OSV reports a fixed version 8.0.5.2. Check the advisory for supported release branches. (source: OSV GHSA-r9jg-fmfx-2gv6) — https://github.com/advisories/GHSA-r9jg-fmfx-2gv6

## Affected products and versions

- rails / rails: >= 8.1, < 8.1.4.1 (affected); < 8.0.5.2 (affected). Source: CNA: GitHub_M
-  / actionpack (actionpack): 8.1.0 (affected, RubyGems); 8.1.1 (affected, RubyGems); 8.1.2 (affected, RubyGems); 8.1.2.1 (affected, RubyGems); 8.1.3 (affected, RubyGems); 8.1.3.1 (affected, RubyGems); 8.1.4 (affected, RubyGems); Ecosystem version events: introduced 8.1; fixed 8.1.4.1. Source: OSV GHSA-r9jg-fmfx-2gv6
-  / actionpack (actionpack): 0.9.0 (affected, RubyGems); 0.9.5 (affected, RubyGems); 1.0.0 (affected, RubyGems); 1.0.1 (affected, RubyGems); 1.1.0 (affected, RubyGems); 1.10.1 (affected, RubyGems); 1.10.2 (affected, RubyGems); 1.11.0 (affected, RubyGems); 1.11.1 (affected, RubyGems); 1.11.2 (affected, RubyGems); 1.12.0 (affected, RubyGems); 1.12.1 (affected, RubyGems); 1.12.2 (affected, RubyGems); 1.12.3 (affected, RubyGems); 1.12.4 (affected, RubyGems); 1.12.5 (affected, RubyGems); 1.13.0 (affected, RubyGems); 1.13.1 (affected, RubyGems); 1.13.2 (affected, RubyGems); 1.13.3 (affected, RubyGems); 1.13.4 (affected, RubyGems); 1.13.5 (affected, RubyGems); 1.13.6 (affected, RubyGems); 1.2.0 (affected, RubyGems); 1.3.0 (affected, RubyGems); 1.3.1 (affected, RubyGems); 1.4.0 (affected, RubyGems); 1.5.0 (affected, RubyGems); 1.5.1 (affected, RubyGems); 1.6.0 (affected, RubyGems); 1.7.0 (affected, RubyGems); 1.8.0 (affected, RubyGems); 1.8.1 (affected, RubyGems); 1.9.0 (affected, RubyGems); 1.9.1 (affected, RubyGems); 2.0.0 (affected, RubyGems); 2.0.1 (affected, RubyGems); 2.0.2 (affected, RubyGems); 2.0.4 (affected, RubyGems); 2.0.5 (affected, RubyGems); 2.1.0 (affected, RubyGems); 2.1.1 (affected, RubyGems); 2.1.2 (affected, RubyGems); 2.2.2 (affected, RubyGems); 2.2.3 (affected, RubyGems); 2.3.10 (affected, RubyGems); 2.3.11 (affected, RubyGems); 2.3.12 (affected, RubyGems); 2.3.14 (affected, RubyGems); 2.3.15 (affected, RubyGems); 2.3.16 (affected, RubyGems); 2.3.17 (affected, RubyGems); 2.3.18 (affected, RubyGems); 2.3.2 (affected, RubyGems); 2.3.3 (affected, RubyGems); 2.3.4 (affected, RubyGems); 2.3.5 (affected, RubyGems); 2.3.6 (affected, RubyGems); 2.3.7 (affected, RubyGems); 2.3.8 (affected, RubyGems); 2.3.8.pre1 (affected, RubyGems); 2.3.9 (affected, RubyGems); 2.3.9.pre (affected, RubyGems); 3.0.0 (affected, RubyGems); 3.0.0.beta (affected, RubyGems); 3.0.0.beta2 (affected, RubyGems); 3.0.0.beta3 (affected, RubyGems); 3.0.0.beta4 (affected, RubyGems); 3.0.0.rc (affected, RubyGems); 3.0.0.rc2 (affected, RubyGems); 3.0.1 (affected, RubyGems); 3.0.10 (affected, RubyGems); 3.0.10.rc1 (affected, RubyGems); 3.0.11 (affected, RubyGems); 3.0.12 (affected, RubyGems); 3.0.12.rc1 (affected, RubyGems); 3.0.13 (affected, RubyGems); 3.0.13.rc1 (affected, RubyGems); 3.0.14 (affected, RubyGems); 3.0.15 (affected, RubyGems); 3.0.16 (affected, RubyGems); 3.0.17 (affected, RubyGems); 3.0.18 (affected, RubyGems); 3.0.19 (affected, RubyGems); 3.0.2 (affected, RubyGems); 3.0.20 (affected, RubyGems); 3.0.3 (affected, RubyGems); 3.0.4 (affected, RubyGems); 3.0.4.rc1 (affected, RubyGems); 3.0.5 (affected, RubyGems); 3.0.5.rc1 (affected, RubyGems); 3.0.6 (affected, RubyGems); 3.0.6.rc1 (affected, RubyGems); 3.0.6.rc2 (affected, RubyGems); 3.0.7 (affected, RubyGems); 3.0.7.rc1 (affected, RubyGems); 3.0.7.rc2 (affected, RubyGems); 3.0.8 (affected, RubyGems); 3.0.8.rc1 (affected, RubyGems); 3.0.8.rc2 (affected, RubyGems); 3.0.8.rc4 (affected, RubyGems); 3.0.9 (affected, RubyGems); 3.0.9.rc1 (affected, RubyGems); 3.0.9.rc3 (affected, RubyGems); 3.0.9.rc4 (affected, RubyGems); 3.0.9.rc5 (affected, RubyGems); 3.1.0 (affected, RubyGems); 3.1.0.beta1 (affected, RubyGems); 3.1.0.rc1 (affected, RubyGems); 3.1.0.rc2 (affected, RubyGems); 3.1.0.rc3 (affected, RubyGems); 3.1.0.rc4 (affected, RubyGems); 3.1.0.rc5 (affected, RubyGems); 3.1.0.rc6 (affected, RubyGems); 3.1.0.rc8 (affected, RubyGems); 3.1.1 (affected, RubyGems); 3.1.1.rc1 (affected, RubyGems); 3.1.1.rc2 (affected, RubyGems); 3.1.1.rc3 (affected, RubyGems); 3.1.10 (affected, RubyGems); 3.1.11 (affected, RubyGems); 3.1.12 (affected, RubyGems); 3.1.2 (affected, RubyGems); 3.1.2.rc1 (affected, RubyGems); 3.1.2.rc2 (affected, RubyGems); 3.1.3 (affected, RubyGems); 3.1.4 (affected, RubyGems); 3.1.4.rc1 (affected, RubyGems); 3.1.5 (affected, RubyGems); 3.1.5.rc1 (affected, RubyGems); 3.1.6 (affected, RubyGems); 3.1.7 (affected, RubyGems); 3.1.8 (affected, RubyGems); 3.1.9 (affected, RubyGems); 3.2.0 (affected, RubyGems); 3.2.0.rc1 (affected, RubyGems); 3.2.0.rc2 (affected, RubyGems); 3.2.1 (affected, RubyGems); 3.2.10 (affected, RubyGems); 3.2.11 (affected, RubyGems); 3.2.12 (affected, RubyGems); 3.2.13 (affected, RubyGems); 3.2.13.rc1 (affected, RubyGems); 3.2.13.rc2 (affected, RubyGems); 3.2.14 (affected, RubyGems); 3.2.14.rc1 (affected, RubyGems); 3.2.14.rc2 (affected, RubyGems); 3.2.15 (affected, RubyGems); 3.2.15.rc1 (affected, RubyGems); 3.2.15.rc2 (affected, RubyGems); 3.2.15.rc3 (affected, RubyGems); 3.2.16 (affected, RubyGems); 3.2.17 (affected, RubyGems); 3.2.18 (affected, RubyGems); 3.2.19 (affected, RubyGems); 3.2.2 (affected, RubyGems); 3.2.2.rc1 (affected, RubyGems); 3.2.20 (affected, RubyGems); 3.2.21 (affected, RubyGems); 3.2.22 (affected, RubyGems); 3.2.22.1 (affected, RubyGems); 3.2.22.2 (affected, RubyGems); 3.2.22.3 (affected, RubyGems); 3.2.22.4 (affected, RubyGems); 3.2.22.5 (affected, RubyGems); 3.2.3 (affected, RubyGems); 3.2.3.rc1 (affected, RubyGems); 3.2.3.rc2 (affected, RubyGems); 3.2.4 (affected, RubyGems); 3.2.4.rc1 (affected, RubyGems); 3.2.5 (affected, RubyGems); 3.2.6 (affected, RubyGems); 3.2.7 (affected, RubyGems); 3.2.7.rc1 (affected, RubyGems); 3.2.8 (affected, RubyGems); 3.2.8.rc1 (affected, RubyGems); 3.2.8.rc2 (affected, RubyGems); 3.2.9 (affected, RubyGems); 3.2.9.rc1 (affected, RubyGems); 3.2.9.rc2 (affected, RubyGems); 3.2.9.rc3 (affected, RubyGems); 4.0.0 (affected, RubyGems); 4.0.0.beta1 (affected, RubyGems); 4.0.0.rc1 (affected, RubyGems); 4.0.0.rc2 (affected, RubyGems); 4.0.1 (affected, RubyGems); 4.0.1.rc1 (affected, RubyGems); 4.0.1.rc2 (affected, RubyGems); 4.0.1.rc3 (affected, RubyGems); 4.0.1.rc4 (affected, RubyGems); 4.0.10 (affected, RubyGems); 4.0.10.rc1 (affected, RubyGems); 4.0.10.rc2 (affected, RubyGems); 4.0.11 (affected, RubyGems); 4.0.11.1 (affected, RubyGems); 4.0.12 (affected, RubyGems); 4.0.13 (affected, RubyGems); 4.0.13.rc1 (affected, RubyGems); 4.0.2 (affected, RubyGems); 4.0.3 (affected, RubyGems); 4.0.4 (affected, RubyGems); 4.0.4.rc1 (affected, RubyGems); 4.0.5 (affected, RubyGems); 4.0.6 (affected, RubyGems); 4.0.6.rc1 (affected, RubyGems); 4.0.6.rc2 (affected, RubyGems); 4.0.6.rc3 (affected, RubyGems); 4.0.7 (affected, RubyGems); 4.0.8 (affected, RubyGems); 4.0.9 (affected, RubyGems); 4.1.0 (affected, RubyGems); 4.1.0.beta1 (affected, RubyGems); 4.1.0.beta2 (affected, RubyGems); 4.1.0.rc1 (affected, RubyGems); 4.1.0.rc2 (affected, RubyGems); 4.1.1 (affected, RubyGems); 4.1.10 (affected, RubyGems); 4.1.10.rc1 (affected, RubyGems); 4.1.10.rc2 (affected, RubyGems); 4.1.10.rc3 (affected, RubyGems); 4.1.10.rc4 (affected, RubyGems); 4.1.11 (affected, RubyGems); 4.1.12 (affected, RubyGems); 4.1.12.rc1 (affected, RubyGems); 4.1.13 (affected, RubyGems); 4.1.13.rc1 (affected, RubyGems); 4.1.14 (affected, RubyGems); 4.1.14.1 (affected, RubyGems); 4.1.14.2 (affected, RubyGems); 4.1.14.rc1 (affected, RubyGems); 4.1.14.rc2 (affected, RubyGems); 4.1.15 (affected, RubyGems); 4.1.15.rc1 (affected, RubyGems); 4.1.16 (affected, RubyGems); 4.1.16.rc1 (affected, RubyGems); 4.1.2 (affected, RubyGems); 4.1.2.rc1 (affected, RubyGems); 4.1.2.rc2 (affected, RubyGems); 4.1.2.rc3 (affected, RubyGems); 4.1.3 (affected, RubyGems); 4.1.4 (affected, RubyGems); 4.1.5 (affected, RubyGems); 4.1.6 (affected, RubyGems); 4.1.6.rc1 (affected, RubyGems); 4.1.6.rc2 (affected, RubyGems); 4.1.7 (affected, RubyGems); 4.1.7.1 (affected, RubyGems); 4.1.8 (affected, RubyGems); 4.1.9 (affected, RubyGems); 4.1.9.rc1 (affected, RubyGems); 4.2.0 (affected, RubyGems); 4.2.0.beta1 (affected, RubyGems); 4.2.0.beta2 (affected, RubyGems); 4.2.0.beta3 (affected, RubyGems); 4.2.0.beta4 (affected, RubyGems); 4.2.0.rc1 (affected, RubyGems); 4.2.0.rc2 (affected, RubyGems); 4.2.0.rc3 (affected, RubyGems); 4.2.1 (affected, RubyGems); 4.2.1.rc1 (affected, RubyGems); 4.2.1.rc2 (affected, RubyGems); 4.2.1.rc3 (affected, RubyGems); 4.2.1.rc4 (affected, RubyGems); 4.2.10 (affected, RubyGems); 4.2.10.rc1 (affected, RubyGems); 4.2.11 (affected, RubyGems); 4.2.11.1 (affected, RubyGems); 4.2.11.2 (affected, RubyGems); 4.2.11.3 (affected, RubyGems); 4.2.2 (affected, RubyGems); 4.2.3 (affected, RubyGems); 4.2.3.rc1 (affected, RubyGems); 4.2.4 (affected, RubyGems); 4.2.4.rc1 (affected, RubyGems); 4.2.5 (affected, RubyGems); 4.2.5.1 (affected, RubyGems); 4.2.5.2 (affected, RubyGems); 4.2.5.rc1 (affected, RubyGems); 4.2.5.rc2 (affected, RubyGems); 4.2.6 (affected, RubyGems); 4.2.6.rc1 (affected, RubyGems); 4.2.7 (affected, RubyGems); 4.2.7.1 (affected, RubyGems); 4.2.7.rc1 (affected, RubyGems); 4.2.8 (affected, RubyGems); 4.2.8.rc1 (affected, RubyGems); 4.2.9 (affected, RubyGems); 4.2.9.rc1 (affected, RubyGems); 4.2.9.rc2 (affected, RubyGems); 5.0.0 (affected, RubyGems); 5.0.0.1 (affected, RubyGems); 5.0.0.beta1 (affected, RubyGems); 5.0.0.beta1.1 (affected, RubyGems); 5.0.0.beta2 (affected, RubyGems); 5.0.0.beta3 (affected, RubyGems); 5.0.0.beta4 (affected, RubyGems); 5.0.0.racecar1 (affected, RubyGems); 5.0.0.rc1 (affected, RubyGems); 5.0.0.rc2 (affected, RubyGems); 5.0.1 (affected, RubyGems); 5.0.1.rc1 (affected, RubyGems); 5.0.1.rc2 (affected, RubyGems); 5.0.2 (affected, RubyGems); 5.0.2.rc1 (affected, RubyGems); 5.0.3 (affected, RubyGems); 5.0.4 (affected, RubyGems); 5.0.4.rc1 (affected, RubyGems); 5.0.5 (affected, RubyGems); 5.0.5.rc1 (affected, RubyGems); 5.0.5.rc2 (affected, RubyGems); 5.0.6 (affected, RubyGems); 5.0.6.rc1 (affected, RubyGems); 5.0.7 (affected, RubyGems); 5.0.7.1 (affected, RubyGems); 5.0.7.2 (affected, RubyGems); 5.1.0 (affected, RubyGems); 5.1.0.beta1 (affected, RubyGems); 5.1.0.rc1 (affected, RubyGems); 5.1.0.rc2 (affected, RubyGems); 5.1.1 (affected, RubyGems); 5.1.2 (affected, RubyGems); 5.1.2.rc1 (affected, RubyGems); 5.1.3 (affected, RubyGems); 5.1.3.rc1 (affected, RubyGems); 5.1.3.rc2 (affected, RubyGems); 5.1.3.rc3 (affected, RubyGems); 5.1.4 (affected, RubyGems); 5.1.4.rc1 (affected, RubyGems); 5.1.5 (affected, RubyGems); 5.1.5.rc1 (affected, RubyGems); 5.1.6 (affected, RubyGems); 5.1.6.1 (affected, RubyGems); 5.1.6.2 (affected, RubyGems); 5.1.7 (affected, RubyGems); 5.1.7.rc1 (affected, RubyGems); 5.2.0 (affected, RubyGems); 5.2.0.beta1 (affected, RubyGems); 5.2.0.beta2 (affected, RubyGems); 5.2.0.rc1 (affected, RubyGems); 5.2.0.rc2 (affected, RubyGems); 5.2.1 (affected, RubyGems); 5.2.1.1 (affected, RubyGems); 5.2.1.rc1 (affected, RubyGems); 5.2.2 (affected, RubyGems); 5.2.2.1 (affected, RubyGems); 5.2.2.rc1 (affected, RubyGems); 5.2.3 (affected, RubyGems); 5.2.3.rc1 (affected, RubyGems); 5.2.4 (affected, RubyGems); 5.2.4.1 (affected, RubyGems); 5.2.4.2 (affected, RubyGems); 5.2.4.3 (affected, RubyGems); 5.2.4.4 (affected, RubyGems); 5.2.4.5 (affected, RubyGems); 5.2.4.6 (affected, RubyGems); 5.2.4.rc1 (affected, RubyGems); 5.2.5 (affected, RubyGems); 5.2.6 (affected, RubyGems); 5.2.6.1 (affected, RubyGems); 5.2.6.2 (affected, RubyGems); 5.2.6.3 (affected, RubyGems); 5.2.7 (affected, RubyGems); 5.2.7.1 (affected, RubyGems); 5.2.8 (affected, RubyGems); 5.2.8.1 (affected, RubyGems); 6.0.0 (affected, RubyGems); 6.0.0.beta1 (affected, RubyGems); 6.0.0.beta2 (affected, RubyGems); 6.0.0.beta3 (affected, RubyGems); 6.0.0.rc1 (affected, RubyGems); 6.0.0.rc2 (affected, RubyGems); 6.0.1 (affected, RubyGems); 6.0.1.rc1 (affected, RubyGems); 6.0.2 (affected, RubyGems); 6.0.2.1 (affected, RubyGems); 6.0.2.2 (affected, RubyGems); 6.0.2.rc1 (affected, RubyGems); 6.0.2.rc2 (affected, RubyGems); 6.0.3 (affected, RubyGems); 6.0.3.1 (affected, RubyGems); 6.0.3.2 (affected, RubyGems); 6.0.3.3 (affected, RubyGems); 6.0.3.4 (affected, RubyGems); 6.0.3.5 (affected, RubyGems); 6.0.3.6 (affected, RubyGems); 6.0.3.7 (affected, RubyGems); 6.0.3.rc1 (affected, RubyGems); 6.0.4 (affected, RubyGems); 6.0.4.1 (affected, RubyGems); 6.0.4.2 (affected, RubyGems); 6.0.4.3 (affected, RubyGems); 6.0.4.4 (affected, RubyGems); 6.0.4.5 (affected, RubyGems); 6.0.4.6 (affected, RubyGems); 6.0.4.7 (affected, RubyGems); 6.0.4.8 (affected, RubyGems); 6.0.5 (affected, RubyGems); 6.0.5.1 (affected, RubyGems); 6.0.6 (affected, RubyGems); 6.0.6.1 (affected, RubyGems); 6.1.0 (affected, RubyGems); 6.1.0.rc1 (affected, RubyGems); 6.1.0.rc2 (affected, RubyGems); 6.1.1 (affected, RubyGems); 6.1.2 (affected, RubyGems); 6.1.2.1 (affected, RubyGems); 6.1.3 (affected, RubyGems); 6.1.3.1 (affected, RubyGems); 6.1.3.2 (affected, RubyGems); 6.1.4 (affected, RubyGems); 6.1.4.1 (affected, RubyGems); 6.1.4.2 (affected, RubyGems); 6.1.4.3 (affected, RubyGems); 6.1.4.4 (affected, RubyGems); 6.1.4.5 (affected, RubyGems); 6.1.4.6 (affected, RubyGems); 6.1.4.7 (affected, RubyGems); 6.1.5 (affected, RubyGems); 6.1.5.1 (affected, RubyGems); 6.1.6 (affected, RubyGems); 6.1.6.1 (affected, RubyGems); 6.1.7 (affected, RubyGems); 6.1.7.1 (affected, RubyGems); 6.1.7.10 (affected, RubyGems); 6.1.7.2 (affected, RubyGems); 6.1.7.3 (affected, RubyGems); 6.1.7.4 (affected, RubyGems); 6.1.7.5 (affected, RubyGems); 6.1.7.6 (affected, RubyGems); 6.1.7.7 (affected, RubyGems); 6.1.7.8 (affected, RubyGems); 6.1.7.9 (affected, RubyGems); 7.0.0 (affected, RubyGems); 7.0.0.alpha1 (affected, RubyGems); 7.0.0.alpha2 (affected, RubyGems); 7.0.0.rc1 (affected, RubyGems); 7.0.0.rc2 (affected, RubyGems); 7.0.0.rc3 (affected, RubyGems); 7.0.1 (affected, RubyGems); 7.0.10 (affected, RubyGems); 7.0.2 (affected, RubyGems); 7.0.2.1 (affected, RubyGems); 7.0.2.2 (affected, RubyGems); 7.0.2.3 (affected, RubyGems); 7.0.2.4 (affected, RubyGems); 7.0.3 (affected, RubyGems); 7.0.3.1 (affected, RubyGems); 7.0.4 (affected, RubyGems); 7.0.4.1 (affected, RubyGems); 7.0.4.2 (affected, RubyGems); 7.0.4.3 (affected, RubyGems); 7.0.5 (affected, RubyGems); 7.0.5.1 (affected, RubyGems); 7.0.6 (affected, RubyGems); 7.0.7 (affected, RubyGems); 7.0.7.1 (affected, RubyGems); 7.0.7.2 (affected, RubyGems); 7.0.8 (affected, RubyGems); 7.0.8.1 (affected, RubyGems); 7.0.8.2 (affected, RubyGems); 7.0.8.3 (affected, RubyGems); 7.0.8.4 (affected, RubyGems); 7.0.8.5 (affected, RubyGems); 7.0.8.6 (affected, RubyGems); 7.0.8.7 (affected, RubyGems); 7.1.0 (affected, RubyGems); 7.1.0.beta1 (affected, RubyGems); 7.1.0.rc1 (affected, RubyGems); 7.1.0.rc2 (affected, RubyGems); 7.1.1 (affected, RubyGems); 7.1.2 (affected, RubyGems); 7.1.3 (affected, RubyGems); 7.1.3.1 (affected, RubyGems); 7.1.3.2 (affected, RubyGems); 7.1.3.3 (affected, RubyGems); 7.1.3.4 (affected, RubyGems); 7.1.4 (affected, RubyGems); 7.1.4.1 (affected, RubyGems); 7.1.4.2 (affected, RubyGems); 7.1.5 (affected, RubyGems); 7.1.5.1 (affected, RubyGems); 7.1.5.2 (affected, RubyGems); 7.1.6 (affected, RubyGems); 7.2.0 (affected, RubyGems); 7.2.0.beta1 (affected, RubyGems); 7.2.0.beta2 (affected, RubyGems); 7.2.0.beta3 (affected, RubyGems); 7.2.0.rc1 (affected, RubyGems); 7.2.1 (affected, RubyGems); 7.2.1.1 (affected, RubyGems); 7.2.1.2 (affected, RubyGems); 7.2.2 (affected, RubyGems); 7.2.2.1 (affected, RubyGems); 7.2.2.2 (affected, RubyGems); 7.2.3 (affected, RubyGems); 7.2.3.1 (affected, RubyGems); 7.2.3.2 (affected, RubyGems); 7.2.4 (affected, RubyGems); 8.0.0 (affected, RubyGems); 8.0.0.1 (affected, RubyGems); 8.0.0.beta1 (affected, RubyGems); 8.0.0.rc1 (affected, RubyGems); 8.0.0.rc2 (affected, RubyGems); 8.0.1 (affected, RubyGems); 8.0.2 (affected, RubyGems); 8.0.2.1 (affected, RubyGems); 8.0.3 (affected, RubyGems); 8.0.4 (affected, RubyGems); 8.0.4.1 (affected, RubyGems); 8.0.5 (affected, RubyGems); 8.0.5.1 (affected, RubyGems); Ecosystem version events: introduced 0; fixed 8.0.5.2. Source: OSV GHSA-r9jg-fmfx-2gv6

## Severity and prioritization

- CVSS 3.1: 4.8 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L; source: CNA: GitHub_M

- CVSS 3.1: 4.8 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.42% as of 2026-11-12; percentile 36.97%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-436

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/rails/rails/security/advisories/GHSA-r9jg-fmfx-2gv6 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/rails/rails/commit/7a955ca36779938267c93902c47d1f55bab99b4b (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/b58c107abe9c1f10c1d6a4941402c60e4dc4742c (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/7a955ca36779938267c93902c47d1f55bab99b4b (security-advisories@github.com)

- https://github.com/rails/rails/commit/b58c107abe9c1f10c1d6a4941402c60e4dc4742c (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (security-advisories@github.com)

- https://github.com/rails/rails/security/advisories/GHSA-r9jg-fmfx-2gv6 (security-advisories@github.com)

- https://github.com/advisories/GHSA-r9jg-fmfx-2gv6 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-r9jg-fmfx-2gv6 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126073; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126073; retrieved 2026-11-11; source updated 2026-11-10

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-r9jg-fmfx-2gv6; retrieved 2026-11-12; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-126073; retrieved 2026-11-12; source updated Not reported

Revision: 03572e5ff918383e27f96f1914c91d8650c32d840c0b908fa823b1e53dbe121c

Canonical: https://y2.dev/cve/CVE-2026-126073

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.