# CVE-2018-6829: Weak cryptography in n/a

> Attackers can obtain sensitive information from ciphertext due to improper ElGamal encoding in Libgcrypt, violating semantic security assumptions.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:** 7 Feb 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-6829, GHSA-wcf7-2f92-j5mv, ROOT-OS-DEBIAN-12-CVE-2018-6829

## What is CVE-2018-6829?

CVE-2018-6829 is a high-severity vulnerability in n/a, published on 7 Feb 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm)

## Which versions are affected by CVE-2018-6829?

It affects 1 product.


Products: Gnupg Libgcrypt.

## How do I fix CVE-2018-6829?

Upgrade to a fixed version.

## Is CVE-2018-6829 being exploited?

There is no known exploitation of CVE-2018-6829 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-3345](https://insights.sbomify.com/CVE-2021-3345/): Memory corruption in n/a (high 7.8)
- [CVE-2026-41989](https://insights.sbomify.com/CVE-2026-41989/): Memory corruption in Libgcrypt (medium 6.7)
- [CVE-2021-40528](https://insights.sbomify.com/CVE-2021-40528/): Weak cryptography in n/a (medium 5.9)
- [CVE-2019-12904](https://insights.sbomify.com/CVE-2019-12904/): Information disclosure in n/a (medium 5.9)
- [CVE-2017-9526](https://insights.sbomify.com/CVE-2017-9526/): Information disclosure in n/a (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-6829 and fix it if it is affected.

What it is: CVE-2018-6829 is a high-severity vulnerability in n/a, published on 7 Feb 2018. 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-2018-6829 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2018-6829/ (Markdown: https://insights.sbomify.com/CVE-2018-6829/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-6829
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-6829
- OSV: https://osv.dev/vulnerability/CVE-2018-6829

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-6829/
Summaries are generated and may contain mistakes; the official description above is the record.