CVE-2026-123863
Node.js is vulnerable to a remote HTTP/2 denial of service via a reachable assertion in Http2Session teardown
A reachable assertion in Node.js HTTP/2 session teardown lets any unauthenticated client abort the server, over both TLS and cleartext. A client can arrange for an Http2Stream that still holds nghttp2-allocated header buffers to outlive its session: the stream is removed from the session's stream set but never detached, so when ~Http2Session() runs the memory accounting is nonzero and the CHECK_EQ(current_nghttp2_memory_, 0) assertion fails, terminating the process. The trigger needs only a default http2 server whose handler responds before the request body has ended, which is typical. It is a variant of CVE-2024-27983 that the earlier fix did not cover, because that fix only detached streams still tracked in the session. This vulnerability affects Node.js 26.x (since 26.9.0) and 24.x (since 24.22.0).
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| node nodejs |
≥ 24.0.0; < 24.22.3 (affected, semver) ≥ 25.0.0; < 26.13.1 (affected, semver) Other versions: unaffected |
CNA: openjs |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.0 / 8.2 high |
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H | CNA: openjs |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://nodejs.org/en/blog/vulnerability/november-2026-security-releasesCNA: openjs · vendor-advisory
- https://cna.openjsf.org/security-advisories.htmlCNA: openjs
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