Information disclosure in Mastodon

CVE-2026-72915

Mastodon is a free, open-source social network server based on ActivityPub. From 4.6.0-beta.1 until 4.6.4 and 4.7.0-beta.1, any logged-in local user could use the show action in app/controllers/admin/collections_controller.rb to access personally identifying information about another local user in a collection because the controller used the general collection policy instead of the admin collection policy namespace. The exposed data included the other user's current email address and last-used IP address. This issue is fixed in versions 4.6.4 and 4.7.0-beta.1.

Vulnerability class: Information Disclosure

Published · last modified .

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:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (39.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-72915: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Mastodon — versions >= 4.6.0-beta.1, < 4.6.4

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-72915?
CVE-2026-72915 is a high-severity vulnerability in Mastodon, classified under Information Disclosure. CVSS score: 7.5/10. Published 2026-08-10.
How severe is CVE-2026-72915?
High severity. CVSS v3 base score is 7.5 out of 10.