---
id: CVE-2026-59825
title: 'Mastodon is a free, open-source social network server based on ActivityPub'
summary: >-
  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…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-295
published: '2026-08-18'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:42:44.293'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-59825'
references:
  - url: >-
      https://github.com/mastodon/mastodon/commit/2ccb6ef277e725d1932295690cf8ab9d3dc03149
    label: security-advisories@github.com
  - url: >-
      https://github.com/mastodon/mastodon/commit/5748d0b16ea09001e0933f76c7afe814e09652ef
    label: security-advisories@github.com
  - url: >-
      https://github.com/mastodon/mastodon/commit/761c61b42590a2fd91442fc15a0a7583e48bbea4
    label: security-advisories@github.com
  - url: 'https://github.com/mastodon/mastodon/pull/39571'
    label: security-advisories@github.com
  - url: 'https://github.com/mastodon/mastodon/releases/tag/v4.4.19'
    label: security-advisories@github.com
  - url: 'https://github.com/mastodon/mastodon/releases/tag/v4.5.12'
    label: security-advisories@github.com
  - url: >-
      https://github.com/mastodon/mastodon/security/advisories/GHSA-3rhr-8phh-jm86
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00373
epssPercentile: 0.28614
ingestedAt: '2026-09-16T13:56:12.591Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.