CVE-2026-41564

#!/usr/bin/perl use CryptX; use strict; use warnings; # Vulnerable Scenario: Create object BEFORE fork my $rsa = Crypt::PK::RSA->new(); # Simulate a preforking server creating workers for my $i (1..2) { my $pid = fork(); die "Cannot fork" unless defined $pid; if ($pid == 0) { # Child process performing cryptographic operations my $priv = Crypt::PK::RSA->new(); # In real vuln, reused 'rsa' object or shared state leads to identical k-values/nonce # If keys are generated or signatures are created, they may share entropy. # Example: Generating a key (vulnerable if PRNG state is identical) $priv->generate_key(256); print "Worker $i generated key fingerprint: " . $priv->key2hash()->{kid_hex} . "\n"; exit 0; } } 1 while wait() != -1; print "Exploit simulation complete. Check if keys/signatures collide.\n";

{"cve": {"id": "CVE-2026-41564", "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "published": "2026-04-23T08:16:01.243", "lastModified": "2026-05-12T13:39:52.800", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "CryptX versions before 0.088 for Perl do not reseed the Crypt::PK PRNG state after forking.\n\nThe 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.\n\nThis affects preforking services such as the Starman web server, where a Crypt::PK::* object loaded at startup is inherited by every worker process."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-335"}, {"lang": "en", "value": "CWE-338"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:dcit:cryptx:*:*:*:*:*:perl:*:*", "versionEndExcluding": "0.088", "matchCriteriaId": "867C8CA7-DE4B-4FA3-9463-54005255A432"}]}]}], "references": [{"url": "https://github.com/DCIT/perl-CryptX/commit/9a1dd3e0c27d68e32450be5538b864c2b115ee15.patch", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "tags": ["Patch"]}, {"url": "https://github.com/DCIT/perl-CryptX/security/advisories/GHSA-24c2-gp6c-24c6", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "tags": ["Vendor Advisory"]}, {"url": "https://metacpan.org/release/MIK/CryptX-0.088", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "tags": ["Product"]}, {"url": "http://www.openwall.com/lists/oss-security/2026/04/23/2", "source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"]}, {"url": "https://github.com/DCIT/perl-CryptX/security/advisories/GHSA-24c2-gp6c-24c6", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Vendor Advisory"]}]}}