A heap out-of-bounds read vulnerability in the libarchive library potentially exposes sensitive memory to remote, unauthenticated attackers.

This is a heap out-of-bounds read flaw (CWE-125) occurring within the RAR archive processing logic, triggered by improper validation of the LZSS sliding window size. The vulnerability allows an unauthenticated, remote attacker to trigger memory disclosure without requiring user interaction.

The ability for an unauthenticated attacker to read sensitive heap memory poses a significant risk to data confidentiality. With a CVSS score of 7.5, this high-severity flaw could lead to the exposure of cryptographic keys, session tokens, or other sensitive information processed by the library. Unauthorized disclosure of such data may facilitate further attacks, resulting in broader system compromise or regulatory non-compliance.

Immediate Action: Apply the vendor-provided security updates for Red Hat Enterprise Linux immediately, ensuring packages are updated to at least the versions specified in the relevant Red Hat Security Advisories (RHSA-2026:10065, RHSA-2026:10097, and others).

Proactive Monitoring: Review system and application logs for abnormal crashes or memory access errors in processes utilizing libarchive, particularly when handling untrusted RAR files.

Compensating Controls: Implement strict input validation or sandboxing for any services that automatically process RAR archives, and utilize memory-safe execution environments where possible to limit the impact of potential memory leaks.

Public Exploit Available: Unknown

Given the potential for unauthorized memory disclosure by unauthenticated actors, this vulnerability should be treated with high priority. Organizations using the affected versions of Red Hat Enterprise Linux must prioritize the application of the vendor patches to mitigate the risk of memory exposure. Failure to patch may result in the silent compromise of sensitive data processed by the library.