httpd mod_auth directory protection bypassed by request path casing on case-insensitive filesystems
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 1 fixed, 4 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Erlang | OTP | 17.0 to before 27.3.4.17; 28.0 to before 28.5.0.6; 29.0 to before 29.0.6 | 27.3.4.17, 28.5.0.6, 29.0.6 | Patch available | CNA |
| Erlang | OTP | 5.10 to before 9.3.2.7; 9.4 to before 9.6.2.3; 9.7 to before 9.7.2 | 9.3.2.7, 9.6.2.3, 9.7.2 | Patch available | CNA |
- OTP VendorErlang Affected 17.0 to before 27.3.4.17; 28.0 to before 28.5.0.6; 29.0 to before 29.0.6 Fixed in 27.3.4.17, 28.5.0.6, 29.0.6 Patch available CNA
- OTP VendorErlang Affected 5.10 to before 9.3.2.7; 9.4 to before 9.6.2.3; 9.7 to before 9.7.2 Fixed in 9.3.2.7, 9.6.2.3, 9.7.2 Patch available CNA
Remediation
- Fix · CNA OTP (Erlang) Fixed in 27.3.4.17, 28.5.0.6, 29.0.6
- Fix · CNA OTP (Erlang) Fixed in 9.3.2.7, 9.6.2.3, 9.7.2
Red Hat 1 advisory
- RHSA-2026:62531 Released 2026-09-02 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images erlang27-27.3.4.17-0.1.hum1@aarch64, erlang27-27.3.4.17-0.1.hum1@src, erlang27-27.3.4.17-0.1.hum1@x86_64 +47
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Erlang OTP 17.0, 27.3.4.17 and 2 more versions
11 records Highest priority Priority MEDIUM 2 MEDIUM, 9 LOW
Other records, highest priority first
- TI-2026-50021 httpd applies no timeout while receiving a request body, parking a worker on a stalled clientPriority MEDIUM 45
- TI-2026-52570 inets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body ReceptionPriority MEDIUM 44
- TI-2026-47459 httpd mod_auth directory protection bypassed by a doubled slash in the request pathPriority LOW 38
- Release ·
Erlang OTP 5.10, 9.3.2.7 and 2 more versions
9 records Highest priority Priority MEDIUM 2 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2026-50021 httpd applies no timeout while receiving a request body, parking a worker on a stalled clientPriority MEDIUM 45
- TI-2026-52570 inets,httpd: Memory Exhaustion via Unenforced max_body_size During Chunked Body ReceptionPriority MEDIUM 44
- TI-2026-47459 httpd mod_auth directory protection bypassed by a doubled slash in the request pathPriority LOW 38
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenStack Platform 13 (Queens) | Affected | No fix yet |
| Red Hat OpenStack Platform 16.2 | Affected | No fix yet |
| Red Hat OpenStack Platform 17.1 | Affected | No fix yet |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet |
| Red Hat Hardened Images | Fixed | RHSA-2026:62531 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-73270
References
Patch 3
More Erlang vulnerabilities
- TI-2025-23504 Erlang/OTP SSH Vulnerable to Pre-Authentication RCE KEVCVSS 3.1CRITICAL 10.0
- TI-2026-48954 httpd parks a request worker indefinitely on a malformed chunk size sent after the headers CVSS 4.0HIGH 8.7
- TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
- TI-2026-71037 Path traversal in rebar3 via unvalidated dependency app names CVSS 4.0HIGH 7.5
- TI-2024-36042 ssl fails to validate incorrect extened key usage CVSS 3.1MEDIUM 5.5
- TI-2020-10791 Rebar3 versions 3.0.0-beta.3 to 3.13.2 are vulnerable to OS command injection via URL… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-73270 · CVE Program
- CVE-2026-73270 · NVD
- FIRST EPSS
- CVE-2026-73270 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences