Description
Crypt::DSA versions before 1.22 for Perl draw the DSA signing nonce and private key from a biased random generator, leading to private-key recovery.
"Crypt::DSA::Util::makerandom forces the high bit of every value it returns to obtain an exactly N-bit integer for prime search. The signing nonce and the private key are drawn from makerandom. Because the high bit is always set, the result is not uniform: its top bit is fixed, producing insecure values."
An attacker who collects a modest number of signatures under an affected key, together with the public key, can recover the private key with a lattice attack.
Keys used to sign with an affected version should be considered compromised and new keys should be generated.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| TIMLEGGE | Crypt::DSA | < 1.22 |
References
- https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.21/source/lib/Crypt/DSA/Util.pm#L56
- https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.22/changes
- https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.22/diff/TIMLEGGE/Crypt-DSA-1.21#lib/Crypt/DSA/Util.pm
- http://www.openwall.com/lists/oss-security/2026/07/05/1
Timeline
- Published
- Jul 5, 2026
- Last modified
- Oct 25, 2026
- NVD status
- Deferred