CVE-2026-73270 httpd mod_auth directory protection bypassed by request path casing on case-insensitive filesystems
Remote attackers can bypass mod_auth directory protection and read protected files on case-insensitive filesystems by exploiting case sensitivity flaws in path matching.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73270?
CVE-2026-73270 is a high-severity authentication bypass vulnerability in Erlang OTP, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Weakness: CWE-178
Which versions are affected by CVE-2026-73270?
How do I fix CVE-2026-73270?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-73270 being exploited?
There is no known exploitation of CVE-2026-73270 in the wild and no public exploit code.
Sources
Also known as AZL-98484, DEBIAN-CVE-2026-73270, EEF-CVE-2026-73270, GHSA-mh78-93cr-jx8f, UBUNTU-CVE-2026-73270.