What’s Vulnerable › Vulnerabilities

CVE-2026-72915: Mastodon: Personally-identifying information disclosure due to incorrect access control validation

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-10 · updated 2026-09-09
• Weakness: CWE-200

Description

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.

Affected products

• mastodon: from 4.6.0-beta.1, < 4.6.4

References

• https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074
• https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b
• https://github.com/mastodon/mastodon/releases/tag/v4.6.4
• https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1
• https://github.com/mastodon/mastodon/security/advisories/GHSA-hx34-2pfw-2qfj

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