{"id":65470,"date":"2026-06-24T14:54:12","date_gmt":"2026-06-24T14:54:12","guid":{"rendered":"https:\/\/zero.redgem.net\/?p=65470"},"modified":"2026-06-24T14:54:12","modified_gmt":"2026-06-24T14:54:12","slug":"mastodon-ssrf-bypass-via-ipv6-unspecified-address","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=65470","title":{"rendered":"Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)_CVE-2026-46348"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. An attacker can use an IP address in the affected range to make Mastodon perform HTTP requests against loopback interfaces, potentially allowing access to otherwise private resources and services. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.&#8221;,&#8221;published&#8221;:&#8221;2026-06-24T19:39:46.332Z&#8221;,&#8221;modified&#8221;:&#8221;2026-06-24T19:39:46.332Z&#8221;,&#8221;type&#8221;:&#8221;cve&#8221;,&#8221;title&#8221;:&#8221;Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)&#8221;,&#8221;source&#8221;:&#8221;GitHub_M&#8221;,&#8221;references&#8221;:&#8221;https:\/\/github.com\/mastodon\/mastodon\/security\/advisories\/GHSA-crr4-7rm4-8gpw&#8221;,&#8221;id&#8221;:&#8221;CVE-2026-46348&#8243;,&#8221;bulletinFamily&#8221;:&#8221;&#8221;,&#8221;cwe&#8221;:[&#8220;CWE-918&#8243;],&#8221;cvelist&#8221;:null,&#8221;sourceData&#8221;:&#8221;mastodon mastodon \\u003e= 4.5.0-beta.1, \\u003c 4.5.10&#8243;,&#8221;sourceHref&#8221;:&#8221;&#8221;,&#8221;cvss&#8221;:{&#8220;score&#8221;:8.7,&#8221;severity&#8221;:&#8221;HIGH&#8221;,&#8221;vector&#8221;:&#8221;CVSS:4.0\/AV:N\/AC:L\/AT:N\/PR:N\/UI:N\/VC:N\/VI:H\/VA:N\/SC:N\/SI:N\/SA:N&#8221;,&#8221;version&#8221;:&#8221;4.0&#8243;},&#8221;cvss2&#8243;:{},&#8221;cvss3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;,&#8221;cvssV3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;}},&#8221;href&#8221;:&#8221;&#8221;,&#8221;category_name&#8221;:&#8221;CVE&#8221;,&#8221;post_link&#8221;:&#8221;&#8221;,&#8221;product&#8221;:&#8221;mastodon&#8221;,&#8221;version&#8221;:&#8221;\\u003e= 4.5.0-beta.1, \\u003c 4.5.10&#8243;,&#8221;vendor&#8221;:&#8221;mastodon&#8221;,&#8221;ai_description&#8221;:&#8221;SSRF Bypass via IPv6 Unspecified Address (::) in Mastodon prior to 4.5.10, 4.4.17, and 4.3.23&#8243;,&#8221;ai_severity&#8221;:&#8221;High&#8221;,&#8221;ai_vendor&#8221;:&#8221;Mastodon&#8221;,&#8221;ai_product&#8221;:&#8221;Mastodon&#8221;,&#8221;ai_version&#8221;:&#8221;4.5.0-beta.1 to 4.5.9, 4.4.0 to 4.4.16, 4.3.0 to 4.3.22&#8243;,&#8221;ai_score&#8221;:8.7}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was&#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":[6,8,19,12,15,13,7,11,5],"class_list":["post-65470","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-cve","tag-cvss","tag-cvss-87","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>Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)_CVE-2026-46348 - 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=65470\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)_CVE-2026-46348 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Mastodon is a free, open-source social network server based on ActivityPub. 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