Bug 2461076 (CVE-2026-41564)

Summary: CVE-2026-41564 perl-cryptx: CryptX: Private key recovery due to predictable pseudo-random number generation after forking
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in CryptX. CryptX versions before 0.088 for Perl do not properly reseed the pseudo-random number generator (PRNG) state after a process forks. This vulnerability allows an attacker to recover the signing private key by observing two signatures from different child processes, as the PRNG state is shared and produces identical output. This issue primarily impacts preforking services that utilize CryptX, such as the Starman web server.
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Bug Depends On: 2461084, 2461085    
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Description OSIDB Bzimport 2026-04-23 08:01:25 UTC 
CryptX versions before 0.088 for Perl do not reseed the Crypt::PK PRNG state after forking.

The Crypt::PK::RSA, Crypt::PK::DSA, Crypt::PK::DH, Crypt::PK::ECC, Crypt::PK::Ed25519 and Crypt::PK::X25519 modules seed a per-object PRNG state in their constructors and reuse it without fork detection. A Crypt::PK::* object created before `fork()` shares byte-identical PRNG state with every child process, and any randomized operation they perform can produce identical output, including key generation. Two ECDSA or DSA signatures from different processes are enough to recover the signing private key through nonce-reuse key recovery.

This affects preforking services such as the Starman web server, where a Crypt::PK::* object loaded at startup is inherited by every worker process.