Mastodon: Persistent anonymous DoS via unhandled NoMethodError in MATH_TRANSFORMER

Description

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.11, 4.4.18, and 4.3.24, a DoS can be triggered by (Uncaught Exception vulerability), due to missing exception handling in the math sanitizer. Malformed <math> nodes can result in a DoS of a whole server or targeted users services, depending on the type of action that includes the malformed nodes and the services interacting with it. This vulnerability is fixed in 4.5.11, 4.4.18, and 4.3.24.

Scores

EPSS (exploitation in 30 days)

0.46% · top 60% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-248: Uncaught Exception (opens in a new tab)All about CWE-248 and its CVEs

Affected products

• mastodon · mastodon

  • affected >= 4.5.0-beta.1, < 4.5.11
  • affected >= 4.4.0-beta.1, < 4.4.18
  • affected < 4.3.24

References (1)

• https://github.com/mastodon/mastodon/security/advisories/GHSA-qrgq-9fx2-vf2r (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-50129](https://trackcve.app/badge/CVE-2026-50129.svg)](https://trackcve.app/cve/CVE-2026-50129)

Record last updated 25 Jun 2026, 13:25 UTC.