CVE-2026-73270
httpd mod_auth directory protection bypassed by request path casing on case-insensitive filesystems
Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a mod_auth protected directory by requesting them with different casing, on deployments whose filesystem is case-insensitive. mod_auth:secret_path/3 decides whether a resolved filesystem path lies inside a protected directory block by running the configured directory path through re:run/3 without the caseless option. A request for /secret/file against a directory configured as /Secret therefore does not match, so the request is treated as unprotected and no authentication challenge is issued, while the filesystem resolves the differently cased path to the same file and mod_get serves it. Deployments on case-sensitive filesystems are unaffected, because there the filesystem itself rejects the mismatched casing. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, OTP 28.5.0.6, and OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, 9.6.2.3, and 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Fixes and workarounds
Workaround
* Host the document root on a case-sensitive filesystem, where the mismatched casing does not resolve to the protected file. * Place a reverse proxy in front of httpd that performs its own case-insensitive path matching for the protected paths, or that normalises request path casing before forwarding. * Restrict access to the server to trusted clients where the deployment allows it.
Source: CNA: EEFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: EEFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: EEFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: EEFAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| OTP Erlang otp
software-id |
≥ 17.0; < * (affected, otp); unaffected at 27.3.4.17; unaffected at 28.5.0.6; unaffected at 29.0.6
Other versions: unknown |
CNA: EEF |
| OTP Erlang inets
otp |
≥ 5.10; < * (affected, otp); unaffected at 9.3.2.7; unaffected at 9.6.2.3; unaffected at 9.7.2
Other versions: unknown |
CNA: EEF |
| OTP Erlang erlang/otp
github |
≥ 84adefa331c4159d432d22840663c38f155cd4c1; < * (affected, git); unaffected at bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6; unaffected at d8878dec0ececc2eab18e47bb18b472f224ca633; unaffected at 9641944a2efbf55bea760f8ff7ba777fe3a0961c ≥ bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6; < * (unaffected, git) ≥ d8878dec0ececc2eab18e47bb18b472f224ca633; < * (unaffected, git) ≥ 9641944a2efbf55bea760f8ff7ba777fe3a0961c; < * (unaffected, git) Other versions: unknown |
CNA: EEF |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.2 high |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | CNA: EEF |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/erlang/otp/security/advisories/GHSA-mh78-93cr-jx8fCNA: EEF · vendor-advisory, related
- https://cna.erlef.org/cves/CVE-2026-73270.htmlCNA: EEF · related
- https://osv.dev/vulnerability/EEF-CVE-2026-73270CNA: EEF · related
- https://www.erlang.org/doc/system/versions.html#order-of-versionsCNA: EEF · x_version-scheme
- https://github.com/erlang/otp/commit/bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6CNA: EEF · patch
- https://github.com/erlang/otp/commit/d8878dec0ececc2eab18e47bb18b472f224ca633CNA: EEF · patch
- https://github.com/erlang/otp/commit/9641944a2efbf55bea760f8ff7ba777fe3a0961cCNA: EEF · patch
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