Vulnerability · Published Jun 24, 2026 · Assigned by GitHub_M

CVE-2026-50129Mastodon: Persistent anonymous DoS via unhandled NoMethodError in MATH_TRANSFORMER

High 7.5

In plain English

A high-severity security flaw 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 0.5% (higher than 40% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 59.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
mastodon	mastodon	>= 4.5.0-beta.1, < 4.5.11>= 4.4.0-beta.1, < 4.4.18< 4.3.24

Weakness: CWE-248 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/mastodon/mastodon/security/advisories/GHSA-qrgq-9fx2-vf2r x_refsource_CONFIRM