CVE-2026-54789
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk33th percentile - higher than 33% of all known CVEs
Summary
mod_auth_openidc before version 2.4.19.4 contains an out-of-bounds read and a one-byte out-of-bounds write in the state-cookie parser. The issue is fixed in version 2.4.19.4.
Risk Assessment
The vulnerability could lead to unauthorized access or server crash, and potentially to code execution, posing a serious security threat.
Recommendation
Upgrade mod_auth_openidc to version 2.4.19.4 or later. As a stop-gap, use a reverse proxy or WAF that rejects malformed Cookie headers.
Other vulnerabilities in mod_auth_openidc
See all- CVE-2017-6059High
Mod_auth_openidc in the Ping Identity OpenID Connect authentication module for Apache before version 2.14 allows remote attackers to spoof page content via a malicious URL provided to the user, triggering an invalid request.
- CVE-2017-6413High
The 'OpenID Connect Relying Party and OAuth 2.0 Resource Server' (mod_auth_openidc) module before version 2.1.6 for the Apache HTTP Server does not skip OIDC_CLAIM_ and OIDCAuthNHeader headers in an 'AuthType oauth20' configuration, allowing remote attackers to bypass authentication via crafted HTTP traffic.
- CVE-2017-6062High
The 'OpenID Connect Relying Party and OAuth 2.0 Resource Server' (mod_auth_openidc) module before version 2.1.5 for the Apache HTTP Server does not skip OIDC_CLAIM_ and OIDCAuthNHeader headers in an 'OIDCUnAuthAction pass' configuration, allowing remote attackers to bypass authentication via crafted HTTP traffic.
- CVE-2025-3891High
A flaw in the mod_auth_openidc module for Apache httpd allows a remote, unauthenticated attacker to trigger a denial of service by sending an empty POST request when the OIDCPreservePost directive is enabled. The server crashes consistently, affecting availability.
Original NVD description (English source)
mod_auth_openidc is an OpenID Certified authentication and authorization module for the Apache 2.x HTTP server that implements the OpenID Connect Relying Party functionality. Prior to 2.4.19.4, an out-of-bounds read and a one-byte out-of-bounds write exist in the state-cookie parser of `mod_auth_openidc`. The issue is fixed in version 2.4.19.4 by stopping the scan at the string terminator so a value-less token is rejected. No in-product workarounds are available. As a stop-gap, an upstream reverse proxy or WAF that rejects or normalizes malformed `Cookie` headers (tokens lacking `=`) can reduce exposure, but upgrading is the recommended remediation.