CVE-2026-22246 json
Local Mastodon users can enumerate and access severed relationships of every other local user
published 2026-01-08 10 mo ago modified 2026-09-08 2 mo ago also BIT-mastodon-2026-22246 , EUVD-2026-1675 , GHSA-ww85-x9cp-5v24
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 19%
- public exploits
- 0
- none known
Summary
Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.
Patch / fix
- bitnami mastodon 4.3.17, 4.4.11, 4.5.4
- joinmastodon mastodon 4.3.17, 4.4.11, 4.5.4
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 10 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| OSV | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| bitnami | mastodon | <4.3.17 >=4.4.0, <4.4.11 >=4.5.0, <4.5.4 |
4.3.17 4.4.11 4.5.4 |
Affected products
- mastodon mastodon
Classification
- Weakness
-
- CWE-201 Insertion of Sensitive Information Into Sent Data
References
-
github.com
/mastodon/mastodon/commit/68e30985ca7afdb89af1b2e9dc962e1993dc8076
patch
-
github.com
/mastodon/mastodon/commit/b2bcd34486fd6681cc0f30028086ef0f47282adf
patch
-
github.com
/mastodon/mastodon/commit/c1fb6893c5175d74c074f6f786d504c8bc610d57
patch
-
github.com
/mastodon/mastodon/security/advisories/GHSA-ww85-x9cp-5v24
third-party-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-22246
web
Sources
- CVE List CVE-2026-22246
- NVD CVE-2026-22246
- OSV BIT-mastodon-2026-22246
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.