Heap-based buffer overflow in Libxml2 - CVE-2026-86138
Published: September 8, 2026
Vulnerability identifier: #VU147356
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-86138
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an integer overflow and resultant heap-based buffer overflow in xmlDictAddQString in dict.c when processing input. A remote attacker can provide crafted input to cause a denial of service.
Affected software
Libxml2
How to mitigate CVE-2026-86138
Install security update from vendor's website.
Libxml2 - update to 2.15.4