CVE-2026-86140 Memory corruption in libxml2
A stack-based buffer overflow in libxml2 allows attackers to execute arbitrary code or cause denial of service via crafted XML input.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-86140?
CVE-2026-86140 is a high-severity memory corruption vulnerability in Xmlsoft Libxml2, published on 5 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow.
Weakness: CWE-121
Which versions are affected by CVE-2026-86140?
It affects 1 product.
Products include Xmlsoft Libxml2.
How do I fix CVE-2026-86140?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-86140 being exploited?
There is no known exploitation of CVE-2026-86140 in the wild and no public exploit code.
Other vulnerabilities in Xmlsoft Libxml2
Sources
Also known as AZL-99717, BELL-CVE-2026-86140, CLSA-2026-1789745061, CLSA-2026-1789745145, CLSA-2026-1789745282, DEBIAN-CVE-2026-86140 and 5 more.