# CVE-2019-11841: Golang/x/crypto message forgery vulnerability

> Attackers can spoof OpenPGP signature headers and prepend arbitrary text to cleartext messages without invalidating signatures, bypassing integrity checks.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 May 2019
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-11841, DLA-1920-1, GHSA-x3jr-pf6g-c48f, GO-2023-1992, UBUNTU-CVE-2019-11841

## What is CVE-2019-11841?

CVE-2019-11841 is a medium-severity vulnerability in Debian Debian Linux, published on 22 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2019-11841?

3 open source packages ship an affected version, including golang.org/x/crypto. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `golang.org/x/crypto` | Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |
| `golang.org/x/crypto` | Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |
| `golang.org/x/crypto` | Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |

Products: Debian Debian Linux, Golang Crypto.

## How do I fix CVE-2019-11841?

Upgrade golang.org/x/crypto to 0.0.0-20190424203555-c05e17bb3b2d or later.

## Is CVE-2019-11841 being exploited?

There is no known exploitation of CVE-2019-11841 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-11841 and fix it if it is affected.

What it is: CVE-2019-11841 is a medium-severity vulnerability in Debian Debian Linux, published on 22 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-11841 in the wild and no public exploit code.

Affected packages and fixed versions:
- golang.org/x/crypto (Go): affected all versions; fixed in 0.0.0-20190424203555-c05e17bb3b2d
- golang.org/x/crypto (Go): affected all versions; fixed in 0.0.0-20190424203555-c05e17bb3b2d
- golang.org/x/crypto (Go): affected all versions; fixed in 0.0.0-20190424203555-c05e17bb3b2d

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-11841/ (Markdown: https://insights.sbomify.com/CVE-2019-11841/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11841
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11841
- OSV: https://osv.dev/vulnerability/CVE-2019-11841

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-11841/
Summaries are generated and may contain mistakes; the official description above is the record.