CVE Explorer

CVE-2026-27477

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 `base_url` that includes or resolves to a local / internal address, leading to the Mastodon server making requests to that address. This only affects Mastodon servers that have opted in to testing the experimental FASP feature by

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:e96722b070f74a299627654ab536c2f0c9f43c8164e691225e3f28cd263c6465

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Affected products and versions

1 source assertion

{"product":"mastodon","vendor":"mastodon","versions":[{"status":"affected","version":">= 4.4.0, < 4.4.14"},{"status":"affected","version":">= 4.5.0, < 4.5.7"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:2fa40a0b5bf0e0a34b48d6d04e51ea201a64c95147c9733e2ed13a6d3689556d · sha256:352307bff80d4d7c… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":4.6,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH"},"metric_type":"cvssV4_0"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:2fa40a0b5bf0e0a34b48d6d04e51ea201a64c95147c9733e2ed13a6d3689556d · sha256:352307bff80d4d7c… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

1 source assertion

{"cweId":"CWE-918","description":"CWE-918: Server-Side Request Forgery (SSRF)","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:2fa40a0b5bf0e0a34b48d6d04e51ea201a64c95147c9733e2ed13a6d3689556d · sha256:352307bff80d4d7c… · /containers/cna/problemTypes/0/descriptions/0

Source references

2 source assertions

{"name":"https://github.com/mastodon/mastodon/commit/7b85d2182361e68d51d9a02f94fb1070b5f503b1","tags":["x_refsource_MISC"],"url":"https://github.com/mastodon/mastodon/commit/7b85d2182361e68d51d9a02f94fb1070b5f503b1"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:2fa40a0b5bf0e0a34b48d6d04e51ea201a64c95147c9733e2ed13a6d3689556d · sha256:352307bff80d4d7c… · /containers/cna/references/1

{"name":"https://github.com/mastodon/mastodon/security/advisories/GHSA-46w6-g98f-wxqm","tags":["x_refsource_CONFIRM"],"url":"https://github.com/mastodon/mastodon/security/advisories/GHSA-46w6-g98f-wxqm"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:2fa40a0b5bf0e0a34b48d6d04e51ea201a64c95147c9733e2ed13a6d3689556d · sha256:352307bff80d4d7c… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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