CVE-2026-55556

A flaw was found in Rsyslog, a system for log processing, specifically in its optional imhttp module. An attacker can remotely trigger a heap buffer overflow by sending a specially crafted, oversized credential to an imhttp endpoint configured for Basic Authentication. This can lead to a system crash, disrupting log collection. This vulnerability affects deployments that have installed, loaded, and use the imhttp module with Basic Authentication.

Red Hat has rated this vulnerability as having an Important severity because an unauthenticated remote network attacker can disrupt the core logging daemon without requiring valid credentials. Exposure is limited to environments where the optional HTTP input module is explicitly enabled with basic authentication enabled. Default Red Hat Enterprise Linux deployments do not configure or load this module and are therefore not susceptible.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.