Description
Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.19 and from 4.5.0 until 4.5.12, Mastodon's app/models/concerns/user/ldap_authenticable.rb mutates OpenSSL::SSL::SSLContext::DEFAULT_PARAMS when LDAP authentication uses LDAP_TLS_NO_VERIFY=true, disabling SSL and TLS certificate verification globally for requests made by puma web processes while sidekiq background jobs remain unaffected. This issue is fixed in versions 4.4.19 and 4.5.12.
References7
- github.com/mastodon/mastodon/commit/2ccb6ef277e725d1932295690cf…
- github.com/mastodon/mastodon/commit/5748d0b16ea09001e0933f76c7a…
- github.com/mastodon/mastodon/commit/761c61b42590a2fd91442fc15a0…
- github.com/mastodon/mastodon/pull/39571
- github.com/mastodon/mastodon/releases/tag/v4.4.19
- github.com/mastodon/mastodon/releases/tag/v4.5.12
- github.com/mastodon/mastodon/security/advisories/GHSA-3rhr-8phh…
Metrics
- CVSS 3.1
-
7.4
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 32 · as of 11 November 2026
- CWE
- CWE-295
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.