CVE-2026-85498

A flaw was found in polkit. When processing input that begins with a null byte, an arithmetic error in the authentication agent helper causes an integer underflow during buffer length calculation, resulting in an out-of-bounds memory read. An attacker capable of supplying crafted input can trigger this flaw, potentially causing an application crash and resulting in a Denial of Service (DoS).

This issue is classified as Low severity because there is no observable effect of the one byte out-of-bounds read. No information disclosure or affect to integrity has been demonstrated.

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.

Mitigation for this issue is either not available or the currently available options do not meet the criteria for a mitigation as defined by the Red Hat Product Security team. This flaw remains subject to future review as new information becomes available. Exposure is limited: the defect is reachable only by a local/adjacent low-privileged user interacting with the polkit authentication agent and results at most in a crash (availability) of the affected process.