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CVE-2026-12205 TIMLEGGE CVE debrief

A vulnerability was discovered in Crypt::DSA versions before 1.21 for Perl, where the nonce was reused across signatures, allowing for private-key recovery. This is due to the caching of per-signature nonce material in the Key object without clearing it. As a result, keys used to sign more than once with an affected version should be considered compromised.

Vendor
TIMLEGGE
Product
Crypt::DSA
CVSS
CRITICAL 9.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-15
Original CVE updated
2026-06-16
Advisory published
2026-06-15
Advisory updated
2026-06-16

Who should care

Developers and users of Crypt::DSA versions before 1.21 for Perl should be aware of this vulnerability and take necessary actions to mitigate the risk.

Technical summary

The Crypt::DSA::sign function caches the per-signature nonce material in the Key object without clearing it. This causes the first sign() on a Key object to pick a nonce, and every later sign() on that same object to reuse it, producing an identical 'r' value.

Defensive priority

high

Recommended defensive actions

  • Upgrade to Crypt::DSA version 1.21 or later.
  • Consider replacing affected keys with new ones.

Evidence notes

The vulnerability was reported on the oss-security mailing list [ref-6]. The issue is documented in the Crypt::DSA source code [ref-4] and changelog [ref-5].

Official resources

CVE-2026-12205 was published on 2026-06-15T23:16:43.150Z.