CVE-2026-77214

A flaw was found in expat. A remote attacker can exploit this vulnerability through repeated parse buffer operations with unvalidated buffer lengths, causing a heap buffer over-read. This issue primarily leads to information disclosure by leaking adjacent heap memory contents, which could assist in bypassing security mitigations such as Address Space Layout Randomization (ASLR), or result in a Denial of Service (DoS) by crashing the application.

This vulnerability is rated as an Important severity because the Expat XML parser is ubiquitous across Red Hat Enterprise Linux environments, frequently handling untrusted inputs in network-facing services and runtime environments. When applications process incoming XML data through repeated chunked parsing calls, an unauthenticated attacker can induce an out-of-bounds heap read without requiring prior privileges. This memory disclosure enables the retrieval of process memory layouts and pointers, effectively weakening ASLR and lowering the barrier for subsequent exploit chains.

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.