CVE-2026-17591: libarchive Use After Free

Vulnerability summary

CVE-2026-17591 is a low (CVSS 3.6) Use After Free vulnerability in libarchive. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.2% of scored vulnerabilities.

Timeline

1. 16-10-2026
   PublishedVulnerability first disclosed.
2. 19-10-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in libarchive. An attacker can cause a Denial of Service (DoS) or potential information disclosure due to a use-after-free vulnerability, which occurs when a program reads memory that has already been released. This issue arises when the archive_entry_copy_mac_metadata() function deallocates an internal buffer before completing a data copy. An attacker who can supply input to an application utilizing this function can trigger the flaw to crash the application or read uninitialized memory data.

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.