What is CVE-2026-47777?

CVE-2026-47777 is a high-severity vulnerability in Mastodon, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-06-15.

How severe is CVE-2026-47777?

High severity. CVSS v3 base score is 7.5 out of 10.

Auth bypass in Mastodon

CVE-2026-47777

Mastodon is a free, open-source social network server based on ActivityPub. In versions there is a missing condition in the check if remote accounts consented to be featured in a remote Collection could lead to attackers bypassing the chec…

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Mastodon — versions >= nightly.2026-03-10, < 4.6.0-beta.1

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity
CWE-863 — Incorrect Authorization

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-47777?: CVE-2026-47777 is a high-severity vulnerability in Mastodon, classified under Insufficient Verification of Data Authenticity. CVSS score: 7.5/10. Published 2026-06-15.
How severe is CVE-2026-47777?: High severity. CVSS v3 base score is 7.5 out of 10.