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Vulnerability · Published Feb 27, 2025 · Assigned by GitHub_M

CVE-2025-27399Mastodon's domain blocks & rationales ignore user approval when visibility set as "users"

Medium 5.3

In plain English

A medium-severity information exposure in mastodon from mastodon. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.4%top 70.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Mastodon is a self-hosted, federated microblogging platform. In versions prior to 4.1.23, 4.2.16, and 4.3.4, when the visibility for domain blocks/reasons is set to "users" (localized English string: "To logged-in users"), users that are not yet approved can view the block reasons. Instance admins that do not want their domain blocks to be public are impacted. Versions 4.1.23, 4.2.16, and 4.3.4 fix the issue.

Affected products (as reported)

VendorProductVersions
mastodon mastodon < 4.1.23>= 4.2.0, < 4.2.16>= 4.3.0, < 4.3.4

Weakness: CWE-200, CWE-285 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References