{"id":57103,"date":"2026-05-26T17:07:53","date_gmt":"2026-05-26T17:07:53","guid":{"rendered":"https:\/\/zero.redgem.net\/?p=57103"},"modified":"2026-05-26T17:07:53","modified_gmt":"2026-05-26T17:07:53","slug":"epa4all-client-vau-signature-bypass","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=57103","title":{"rendered":"epa4all-client: VAU Signature bypass_CVE-2026-44900"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;epa4all-client is the Java Client for epa4all \/ ePA 3.0 in the Telematik Infrastruktur. Prior to 1.2.1, in  SignedPublicKeysTrustValidatorImpl.isTrusted(), the ECDSA signature verification at line 45 discards the boolean return value of Signature.verify(). The method performs certificate chain validation, OCSP check, and signature algorithm setup, but never checks whether the signature actually matches. For any structurally valid signature, it returns true.  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Prior to 1.2.1, in SignedPublicKeysTrustValidatorImpl.isTrusted(), the ECDSA signature verification at line&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[6,8,52,12,15,13,7,11,5],"class_list":["post-57103","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-cve","tag-cvss","tag-cvss-81","tag-exploit","tag-high","tag-news","tag-security","tag-tapic","tag-vulnerability"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>epa4all-client: VAU Signature bypass_CVE-2026-44900 - zero redgem<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/zero.redgem.net\/?p=57103\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"epa4all-client: VAU Signature bypass_CVE-2026-44900 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;epa4all-client is the Java Client for epa4all \/ ePA 3.0 in the Telematik Infrastruktur. 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