SB2026042381 - Allocation of Resources Without Limits or Throttling in Mastodon

Description

This security bulletin contains information about 1 vulnerability.

1) Allocation of Resources Without Limits or Throttling (CVE-ID: CVE-2025-54879)

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to allocation of resources without limits or throttling in the confirmation email throttle for the /auth/confirmation endpoint when handling confirmation email requests. A remote attacker can send repeated POST requests with the same email address to cause a denial of service.

By rotating IP addresses, requests can avoid the remaining IP-based throttle and target unconfirmed email addresses.

Remediation

Install update from vendor's website.

References

• https://github.com/mastodon/mastodon/security/advisories/GHSA-84ch-6436-c7mg
• https://github.com/advisories/GHSA-84ch-6436-c7mg