Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a… (CVE-2026-73270)
A vulnerability in Erlang/OTP inets httpd allows remote unauthenticated attackers to bypass authentication and read files inside mod_auth protected directories on case-insensitive filesystems by exploiting improper handling of case sensitivity in request paths. This affects multiple versions of Erlang/OTP from 17.0 up to but not including patched versions 27.3.4.17, 28.5.0.6, and 29.0.6. The issue arises because the authentication check does not consider case-insensitive matches, while the filesystem resolves paths case-insensitively, allowing unauthorized access. A fix is available and has been released by Ubuntu in security updates.
AI Analysis
Technical Summary
The vulnerability (CVE-2026-73270) in Erlang/OTP inets httpd concerns improper handling of case sensitivity in HTTP request paths. The mod_auth:secret_path/3 function checks if a requested path lies within a protected directory by matching directory paths without the caseless option, causing mismatches when the request path casing differs from the configured directory path. On case-insensitive filesystems, this mismatch allows requests with different casing to bypass authentication and access protected files. This affects OTP versions from 17.0 before 27.3.4.17, 28.0 before 28.5.0.6, and 29.0 before 29.0.6, corresponding to inets versions from 5.10 before 9.3.2.7, 9.4 before 9.6.2.3, and 9.7 before 9.7.2. The vulnerability does not affect case-sensitive filesystems. Ubuntu has released patches addressing this issue.
Potential Impact
Remote unauthenticated attackers can bypass HTTP authentication protections on mod_auth protected directories by exploiting case-insensitive filesystem behavior combined with case-sensitive path checks, allowing unauthorized reading of protected files. This can lead to unauthorized disclosure of sensitive information. The vulnerability is limited to deployments on case-insensitive filesystems; case-sensitive filesystems are not affected.
Mitigation Recommendations
A patch is available and should be applied to affected Erlang/OTP versions. Ubuntu has released security updates addressing this vulnerability (see https://ubuntu.com/security/notices/USN-8827-1). Systems should be updated to the fixed package versions provided by the vendor. No additional mitigation is required once patched.
Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a… (CVE-2026-73270)
Description
A vulnerability in Erlang/OTP inets httpd allows remote unauthenticated attackers to bypass authentication and read files inside mod_auth protected directories on case-insensitive filesystems by exploiting improper handling of case sensitivity in request paths. This affects multiple versions of Erlang/OTP from 17.0 up to but not including patched versions 27.3.4.17, 28.5.0.6, and 29.0.6. The issue arises because the authentication check does not consider case-insensitive matches, while the filesystem resolves paths case-insensitively, allowing unauthorized access. A fix is available and has been released by Ubuntu in security updates.
CVSS v4.0
Affected software
pkg:deb/ubuntu/erlang?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/erlang?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/erlang?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/erlang?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/erlang?arch=source&distro=jammypkg:deb/ubuntu/erlang?arch=source&distro=noblepkg:deb/ubuntu/erlang?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CVE-2026-73270) in Erlang/OTP inets httpd concerns improper handling of case sensitivity in HTTP request paths. The mod_auth:secret_path/3 function checks if a requested path lies within a protected directory by matching directory paths without the caseless option, causing mismatches when the request path casing differs from the configured directory path. On case-insensitive filesystems, this mismatch allows requests with different casing to bypass authentication and access protected files. This affects OTP versions from 17.0 before 27.3.4.17, 28.0 before 28.5.0.6, and 29.0 before 29.0.6, corresponding to inets versions from 5.10 before 9.3.2.7, 9.4 before 9.6.2.3, and 9.7 before 9.7.2. The vulnerability does not affect case-sensitive filesystems. Ubuntu has released patches addressing this issue.
Potential Impact
Remote unauthenticated attackers can bypass HTTP authentication protections on mod_auth protected directories by exploiting case-insensitive filesystem behavior combined with case-sensitive path checks, allowing unauthorized reading of protected files. This can lead to unauthorized disclosure of sensitive information. The vulnerability is limited to deployments on case-insensitive filesystems; case-sensitive filesystems are not affected.
Mitigation Recommendations
A patch is available and should be applied to affected Erlang/OTP versions. Ubuntu has released security updates addressing this vulnerability (see https://ubuntu.com/security/notices/USN-8827-1). Systems should be updated to the fixed package versions provided by the vendor. No additional mitigation is required once patched.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-73270
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
- Cvss Version
- 4.0
- State
- PUBLISHED
Patch Information
Threat ID: 6abb4193f7a7c54106cc3801
Added to database: 09/29/2026, 04:41:55 UTC
Last enriched: 09/29/2026, 04:50:43 UTC
Last updated: 09/29/2026, 18:13:10 UTC
Views: 3
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.