Medium 4.3Published Oct 21, 2025

CVE-2025-62605Mastodon is a free, open-source social network server based on ActivityPub.

Updated under an hour ago (2026-10-19 10:00 UTC)

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It affects joinmastodon mastodon. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for joinmastodon mastodon

Exploited in the last 30 days

Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon version 4.4, support for verifiable quote posts with quote controls was added, but it is possible for an attacker to bypass these controls in Mastodon versions prior to 4.4.8 and 4.5.0-beta.2. Mastodon internally treats reblogs as statuses. Since they were not special-treated, an attacker could reblog any post, then quote their reblog, technically quoting themselves, but having the quote feature a preview of the post they did not get authorization for with all of the affordances that would be otherwise denied by the quote controls. This issue has been patched in versions 4.4.8 and 4.5.0-beta.2.

CVSS: 4.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE): CWE-754
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

joinmastodon mastodon joinmastodon:mastodon	from 4.4.0 before 4.4.8; 4.5.0	NVD

References

https://github.com/mastodon/mastodon/commit/2dc4552229b55e2e4adaef675e68ed7ae123d78epatch
https://github.com/mastodon/mastodon/commit/405a49df44033e7d179f3d44d59fb68a67d54789patch
https://github.com/mastodon/mastodon/releases/tag/v4.4.8release-notes
https://github.com/mastodon/mastodon/releases/tag/v4.5.0-beta.2release-notes
https://github.com/mastodon/mastodon/security/advisories/GHSA-8h43-rcqj-wpc6vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.