{"id":35198,"date":"2026-01-12T16:52:48","date_gmt":"2026-01-12T16:52:48","guid":{"rendered":"http:\/\/localhost\/?p=35198"},"modified":"2026-01-12T16:52:48","modified_gmt":"2026-01-12T16:52:48","slug":"fulcio-vulnerable-to-server-side-request-forgery-ssrf-via-metaissuer-regex-bypass","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=35198","title":{"rendered":"Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass_CVE-2026-22772"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.5, Fulcio&#8217;s metaRegex() function uses unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF. 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Prior to 1.8.5, Fulcio&#8217;s metaRegex() function uses unanchored regex,&#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":[6,8,90,12,21,13,7,11,5],"class_list":["post-35198","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-cve","tag-cvss","tag-cvss-58","tag-exploit","tag-medium","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>Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass_CVE-2026-22772 - 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=35198\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass_CVE-2026-22772 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. 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