Back to overview

CVE-2026-50128

MEDIUM
5.3
CVSS 3.1
Description
Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18, Mastodon has a feature to let websites credit authors of their articles. To prevent false attribution claims, Mastodon uses the attributionDomains JSON-LD term, however, an error in how it is defined makes Linked Data Signatures on the toot:attributionDomains property ineffective. An attacker can arbitrarily modify the attributionDomains value of a legitimately signed Update activity and bypass Mastodon’s signature verification. This vulnerability is fixed in 4.5.11 and 4.4.18.

Metadata

CVE ID
CVE-2026-50128
State
PUBLISHED
Assigner
GitHub_M
Reserved
2026-06-03 18:49 UTC
Published
2026-06-24 19:48 UTC
Last updated
2026-06-24 19:48 UTC
Primary CWE
CWE-354
CWE-354: Improper Validation of Integrity Check Value
Vendor / Product
mastodon / mastodon
Sources
cve.org  ·  NVD

Severity & Metrics

5.3 MEDIUM CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Affected products (1)
VendorProductPlatformVersions
mastodon mastodon — >= 4.5.0-beta.1, < 4.5.11, >= 4.3.0, < 4.4.18
Weakness (CWE)
CWESourceDescription
CWE-354 cna CWE-354: Improper Validation of Integrity Check Value
CVSS scores (1)
ScoreSeverityVersionSourceVector
5.3 MEDIUM 3.1 cna CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References (1)
Back to overview