High 7.4Published Aug 18, 2026

CVE-2026-59825Mastodon: Unwanted deactivation of SSL/TLS certificate verification

Updated under an hour ago (2026-10-19 08:23 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-295
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 18, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

mastodon mastodon mastodon:mastodon (from the name)	before 4.4.19; from 4.5.0, < 4.5.12	CNA record

References

https://github.com/mastodon/mastodon/security/advisories/GHSA-3rhr-8phh-jm86x-refsource-confirm
https://github.com/mastodon/mastodon/pull/39571x-refsource-misc
https://github.com/mastodon/mastodon/commit/2ccb6ef277e725d1932295690cf8ab9d3dc03149x-refsource-misc
https://github.com/mastodon/mastodon/commit/5748d0b16ea09001e0933f76c7afe814e09652efx-refsource-misc
https://github.com/mastodon/mastodon/commit/761c61b42590a2fd91442fc15a0a7583e48bbea4x-refsource-misc
https://github.com/mastodon/mastodon/releases/tag/v4.4.19x-refsource-misc
https://github.com/mastodon/mastodon/releases/tag/v4.5.12x-refsource-misc

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.