CVE-2026-86143

An integer overflow in the libxml2 xmlIO module occurs when data backlogs exceed maximum integer limits. This flaw passes negative length values to downstream write callbacks, creating an unsafe state that can lead to data corruption or compromise application confidentiality and integrity.

Moderate impact: This flaw in libxml2, a widely used XML parsing library, is due to an integer overflow in write callbacks. This can lead to negative lengths being passed to write operations, potentially causing data integrity issues in applications that process untrusted XML input and utilize affected write callbacks. The impact is limited to applications that specifically trigger this overflow condition.

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.

Cap process and cgroup memory so a process cannot build a ≥2 GiB libxml2 output backlog. Keep FORTIFY_SOURCE-built Red Hat binaries so some callback copies of the truncated length abort instead of corrupting memory