CVE-2026-111137 libsmi through 0.5.0 Out-of-Bounds Write via smiValueAsString OCTET STRING DEFVAL
Attackers can cause out-of-bounds writes and crashes in libsmi consumers by supplying crafted MIB files with large OCTET STRING values.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-111137?
CVE-2026-111137 is a medium-severity memory corruption vulnerability in amartin755 libsmi, published on 15 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
libsmi through 0.5.0 contains an out-of-bounds write vulnerability in smiValueAsString() in lib/smi.c that allows attackers to overflow a fixed 1024-byte static buffer through hex rendering of OCTET STRING values. Attackers can supply a crafted MIB with an OCTET STRING DEFVAL of 512 or more octets and a leading 0x00 byte to corrupt adjacent library globals and crash smidump or other consumers.
Weakness: CWE-787
Which versions are affected by CVE-2026-111137?
How do I fix CVE-2026-111137?
No fix has been published for CVE-2026-111137 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-111137 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111137 exists.
Sources
Also known as AZL-108296, DEBIAN-CVE-2026-111137, ECHO-0f04-0e7e-a4bf, GHSA-xxf8-vfhv-w73c, UBUNTU-CVE-2026-111137.