Amazon Linux 2027 Preview Security Advisory: ALAS2027-2026-004
Advisory Release Date: 2026-09-18 09:00 Pacific
Advisory Updated Date: 2026-09-18 09:00 Pacific
Severity:
Important
Issue Overview:
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. (CVE-2026-54789)
Affected Packages:
mod_auth_openidc
Issue Correction:
Run yum update mod_auth_openidc to update your system.
New Packages:
aarch64:
mod_auth_openidc-debuginfo-2.4.19.2-1.amzn2027.0.1.aarch64
mod_auth_openidc-2.4.19.2-1.amzn2027.0.1.aarch64
mod_auth_openidc-debugsource-2.4.19.2-1.amzn2027.0.1.aarch64
src:
mod_auth_openidc-2.4.19.2-1.amzn2027.0.1.src
x86_64:
mod_auth_openidc-debugsource-2.4.19.2-1.amzn2027.0.1.x86_64
mod_auth_openidc-debuginfo-2.4.19.2-1.amzn2027.0.1.x86_64
mod_auth_openidc-2.4.19.2-1.amzn2027.0.1.x86_64