What is CVE-2026-33869?

CVE-2026-33869 is a medium-severity vulnerability in Mastodon, classified under Incorrect Authorization. CVSS score: 4.8/10. Published 2026-03-27.

How severe is CVE-2026-33869?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Auth bypass in Mastodon

CVE-2026-33869

Mastodon is a free, open-source social network server based on ActivityPub. In versions on the 4.5.x branch prior to 4.5.8 and on the 4.4.x branch prior to 4.4.15, an attacker that knows of a quote before it has reached a server can preven…

Vulnerability class: Broken Access Control

EPSS: 0.001 (23.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L.

Affected products

Mastodon — versions >= 4.5.0, < 4.5.8, >= 4.4.0, < 4.4.15

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

https://github.com/mastodon/mastodon/security/advisories/GHSA-q4g8-82c5-9h33 (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-33869?: CVE-2026-33869 is a medium-severity vulnerability in Mastodon, classified under Incorrect Authorization. CVSS score: 4.8/10. Published 2026-03-27.
How severe is CVE-2026-33869?: Medium severity. CVSS v3 base score is 4.8 out of 10.