CVE-2026-27477 Mastodon has SSRF via unvalidated FASP Provider base_url

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, an unauthenticated attacker can register a FASP with an attacker-chosen baseurl that includes or...

CVE-2026-27477

Mastodon CVE-2026-27477 describes an SSRF risk in the FASP feature: unauthenticated registration of a FASP with a base_url that can resolve to an internal address, when the server has EXPERIMENTAL_FEATURES including fasp enabled. Affected: Mastodon versions 4.4.0–4.4.13 and 4.5.0–4.5.6. Impact: s...

CVE-2026-27468

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content...

CVE-2026-27468

CVE-2026-27468 (Mastodon) affects Mastodon servers that have enabled the experimental FASP feature via EXPERIMENTAL_FEATURES including “fasp”. In versions 4.4.0–4.4.13 and 4.5.0–4.5.6, actions by a FASP to subscribe to account/content lifecycle events or to backfill content did not verify adminis...

CVE-2026-27468 Mastodon may allow unconfirmed FASP to make subscriptions

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content...

CVE-2026-27468 Mastodon may allow unconfirmed FASP to make subscriptions

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content...

CVE-2026-27468

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content...

CVE-2026-27468 Mastodon may allow unconfirmed FASP to make subscriptions

Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content...

CVE-2026-27202

creationtimestamp| type| source ---|---|--- 2026-02-24 16:07:30+00:00| seen| https://bsky.app/profile/thehackerwire.bsky.social/post/3mfmkessg5i2s 2026-02-24 16:07:36+00:00| seen| https://mastodon.social/ap/users/115755483699003887/statuses/116126464556997178...

Mastodon 代码问题漏洞

Mastodon is an open-source social networking server based on ActivityPub, developed by Mastodon. There are code vulnerabilities in versions 4.4.0 to 4.4.13 and 4.5.0 to 4.5.6 of Mastodon. These vulnerabilities allow unverified attackers to register a FASP with a baseurl pointing to a local intern...

Mastodon 安全漏洞

Mastodon is an open-source social networking server based on ActivityPub, developed by Mastodon. Vulnerabilities exist in versions 4.4.0 to 4.4.13 and 4.5.0 to 4.5.6 of Mastodon. These vulnerabilities stem from FASP failing to properly check whether subscription account content lifecycle events o...

PT-2026-21779

Name of the Vulnerable Software and Affected Versions Mastodon versions 4.4.0 through 4.4.13 Mastodon versions 4.5.0 through 4.5.6 Description Mastodon is a free, open-source social network server based on ActivityPub. The issue relates to FASP Federated Actor Subscription Protocol registration,...

PT-2026-21343

Name of the Vulnerable Software and Affected Versions Mastodon versions 4.4.0 through 4.4.13 Mastodon versions 4.5.0 through 4.5.6 Description Mastodon is a free, open-source social network server based on ActivityPub. A flaw exists in FASP registration where an unauthenticated attacker can...

CVE-2025-4521

creationtimestamp| type| source ---|---|--- 2026-02-19 17:16:38+00:00| seen| https://bsky.app/profile/thehackerwire.bsky.social/post/3mfa3vuahhi2d 2026-02-19 17:16:50+00:00| seen| https://mastodon.social/ap/users/115755483699003887/statuses/116098424956279178...

CVE-2025-70149

creationtimestamp| type| source ---|---|--- 2026-02-18 19:37:30+00:00| seen| https://bsky.app/profile/thehackerwire.bsky.social/post/3mf5tcqkdiw2x 2026-02-18 19:37:49+00:00| seen| https://mastodon.social/ap/users/115755483699003887/statuses/116093316812596790 2026-02-18 19:37:59+00:00| seen|...

BIT-MASTODON-2026-25540 Mastodon's signature-dependent ActivityPub collection responses cached under signature-independent keys (Web Cache Poisoning via `Rails.cache`)

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via Rails.cache. When AUTHORIZEDFETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that...

CVE-2026-25540

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via Rails.cache. When AUTHORIZEDFETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that...

CVE-2026-25540

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via Rails.cache. When AUTHORIZEDFETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that...

CVE-2026-25540

Mastodon prior to versions 4.3.19, 4.4.13, and 4.5.6 is vulnerable to web cache poisoning in Rails.cache when AUTHORIZED_FETCH is enabled. The ActivityPub endpoints for pinned posts and featured hashtags cache responses that depend on the signer’s account, but the internal cache reuse does not re...

EUVD-2026-5329

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via Rails.cache. When AUTHORIZEDFETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that...