{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/tags/certificate-bypass/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["JDK"],"_cs_severities":["high"],"_cs_tags":["certificate-bypass","defense-evasion","java","supply-chain"],"_cs_type":"advisory","_cs_vendors":["Oracle"],"content_html":"\u003cp\u003eSonatype researchers confirmed that Java's \u003ccode\u003eblocked.certs\u003c/code\u003e mechanism, used to mitigate the October 2026 eMudhra certificate authority compromise, is susceptible to bypass. Because the blocklist relies on exact SHA-256 byte-level fingerprints, attackers can alter the binary encoding of a compromised certificate without invalidating its signature. If the re-encoded certificate is still accepted by the trust store, it bypasses the blocklist. This was demonstrated using both ECDSA (altering signature representation from \u003cem\u003es\u003c/em\u003e to \u003cem\u003en-s\u003c/em\u003e) and RSA (removing NULL parameters from signature algorithm identifiers) encodings.\u003c/p\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eThe bypass allows compromised intermediate CA certificates to remain trusted in Java environments even if their original fingerprints are added to \u003ccode\u003eblocked.certs\u003c/code\u003e. This could facilitate the issuance and acceptance of fraudulent certificates by applications relying on the Java trust store, despite vendor-provided mitigation attempts.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eAudit Java runtime trust stores to identify and remove root certificates associated with the compromised eMudhra infrastructure rather than relying solely on the \u003ccode\u003eblocked.certs\u003c/code\u003e file.\u003c/li\u003e\n\u003cli\u003eTest certificate chain validation for critical services using both original and potential re-encoded variants of compromised intermediates.\u003c/li\u003e\n\u003cli\u003eMonitor Java application logs for TLS handshake failures or unusual certificate validation outcomes following updates to trust stores.\u003c/li\u003e\n\u003cli\u003eCoordinate with infrastructure and development teams before modifying trust stores to avoid disrupting legitimate TLS connections.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-10-22T03:36:55Z","date_published":"2026-10-22T03:36:55Z","id":"https://feed.craftedsignal.io/briefs/2026-10-java-certificate-bypass/","summary":"Researchers identified that Java’s certificate blocklist (blocked.certs) can be bypassed for compromised certificates by re-encoding them to produce different SHA-256 fingerprints while maintaining signature validity.","title":"Java: Certificate revocation bypass via alternative certificate encoding","url":"https://feed.craftedsignal.io/briefs/2026-10-java-certificate-bypass/"}],"language":"en","title":"CraftedSignal Threat Feed - Certificate-Bypass","version":"https://jsonfeed.org/version/1.1"}