---
id: CVE-2026-111137
title: >-
  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
summary: >-
  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 …
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H'
cwe:
  - CWE-787
vendor: amartin755
product: libsmi
affected:
  - libsmi <= 0.5.0
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:17:27.690'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-111137'
references:
  - url: 'https://github.com/amartin755/libsmi'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/amartin755/libsmi/blob/c58307210fe995ec419db976eb234aebc71a9216/lib/smi.c#L479-L566
    label: disclosure@vulncheck.com
  - url: >-
      https://hackmd.io/@haind-pwn/libsmi-smivalueasstring-octetstring-defval-oob-write
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/libsmi-through-0.5.0-out-of-bounds-write-via-smivalueasstring-octet-string-defval
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-15T19:25:46.410Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.