# CVE-2026-12205: Crypt::DSA versions before 1.21 for Perl reused the nonce across signatures, leading to private-key recovery

> Reusing nonces in Crypt::DSA allows private key recovery, compromising all keys signed with affected versions.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** No
- **Published:** 15 Jun 2026
- **Updated:** 16 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-12205, GHSA-88g7-87jg-w4q9, UBUNTU-CVE-2026-12205

## What is CVE-2026-12205?

CVE-2026-12205 is a critical vulnerability in TIMLEGGE Crypt::DSA, published on 15 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Crypt::DSA versions before 1.21 for Perl reused the nonce across signatures, leading to private-key recovery.

Crypt::DSA::sign caches the per-signature nonce material in the Key object without ever clearing it.

The first sign() on a Key object picks a nonce, and every later sign() on that same object reuses it, producing an identical "r".

Keys used to sign more than once with an affected version should be considered compromised.

Weakness: CWE-323 (Reusing a Nonce, Key Pair in Encryption)

## Which versions are affected by CVE-2026-12205?


## How do I fix CVE-2026-12205?

No fix has been published for CVE-2026-12205 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12205 being exploited?

There is no known exploitation of CVE-2026-12205 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12205 and fix it if it is affected.

What it is: CVE-2026-12205 is a critical vulnerability in TIMLEGGE Crypt::DSA, published on 15 Jun 2026. 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-2026-12205 in the wild and no public exploit code.

Affected product: TIMLEGGE Crypt::DSA. 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-2026-12205/ (Markdown: https://insights.sbomify.com/CVE-2026-12205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12205
- OSV: https://osv.dev/vulnerability/CVE-2026-12205

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12205/
Summaries are generated and may contain mistakes; the official description above is the record.