CVE-2026-27477

mediumPriorität · verfolgen · 24EPSS 0.003 · 24. PerzentilEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.31% (24th) EPSS
CVSS 5.9 · medium
Is it mine?
6 products
Prüfe deine Angriffsfläche
Who says so?
4 sources
cnnvd · enisa_euvd · osv · nvd

EPSS · bewertet 2026-10-27

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 setting the environment variable `EXPERIMENTAL_FEATURES` to a value including `fasp`. An attacker can force the Mastodon server to make http(s) requests to internal systems. While they cannot control the full URL that is being requested (only the prefix) and cannot see the result of those requests, vulnerabilities or other undesired behavior could be triggered in those systems. The fix is included in the 4.4.14 and 4.5.7 releases. Admins that are actively testing the experimental "fasp" feature should update their systems. Servers not using the experimental feature flag `fasp` are not affected.

01

cvss

Technischer Schweregrad, 0–10. Eine Zeile je Quelle.

5.9
010

Basiswert 0–10 · höher = schwerwiegender · Vektor überfahren zum Auflösen

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:Nprimary · NVD / NIST USAusnutzbarkeit 2.2 · Auswirkung 3.6
v4.04.6mediumCVSS: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:Usecondary · ENISA EU
v4.04.6mediumCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · security-advisories@github.com
v4.04.6mediumCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)
02

schwächen

Die CWE-Schwächeklassen, zu denen dies gehört.

03

betroffene Produkte (6)

Betroffene Produkte und Versionsbereiche.

04

Advisories (1)

Hersteller- und Ökosystem-Meldungen dazu.

  • BIT-mastodon-2026-27477Mastodon has SSRF via unvalidated FASP Provider base_url2026-03-02vendor · osvUS

    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 setting the environment variable `EXPERIMENTAL_FEATURES` to a value including `fasp`. An attacker can force the Mastodon server to make http(s) requests to internal systems. While they cannot control the full URL that is being requested (only the prefix) and cannot see the result of those requests, vulnerabilities or other undesired behavior could be triggered in those systems. The fix is included in the 4.4.14 and 4.5.7 releases. Admins that are actively testing the experimental "fasp" feature should update their systems. Servers not using the experimental feature flag `fasp` are not affected.

05

auch bekannt als (3)

Weitere Namen und Kennungen dieser Entität.

06

quellen

Welche Quellen diesen Datensatz belegen und wann.

veröffentlicht 2026-02-24geändert 2026-06-17
07

Referenzen (7)

Externe Belege — Patches, Meldungen, Analysen.

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