CVE-2026-59825

Status: DeferredHigh (7.4)—

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

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Base score: 7.4

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.37%
Percentile among all scored CVEs: 29
Score date: 10/6/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access75 %
Primary impactT1557 Adversary-in-the-Middlecredential access · collection80 %
Secondary impactT1078 Valid Accountsstealth · persistence · privilege escalation · initial access65 %

Vulnerabilidad de verificación SSL/TLS deshabilitada globalmente (CWE-295) en servidor Mastodon accesible en red, permitiendo ataque MITM para interceptar credenciales LDAP o sesiones, e impersonación de identidad (T1078) sin validación de certificados.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

User Training Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Developer Guidance

Affected technologies (2)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Joinmastodon — Mastodon^AI Openssl — Openssl^AI

CWEs

CWE-295

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-59825",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-59825",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-18T15:51:09.488217Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.4,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 2.2
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "mastodon",
          "product": "mastodon",
          "versions": [
            {
              "status": "affected",
              "version": "< 4.4.19"
            },
            {
              "status": "affected",
              "version": ">= 4.5.0, < 4.5.12"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-08-18T15:16:55.623",
  "references": [
    {
      "url": "https://github.com/mastodon/mastodon/commit/2ccb6ef277e725d1932295690cf8ab9d3dc03149",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/mastodon/mastodon/commit/5748d0b16ea09001e0933f76c7afe814e09652ef",
      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/mastodon/mastodon/commit/761c61b42590a2fd91442fc15a0a7583e48bbea4",
      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/mastodon/mastodon/pull/39571",
      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/mastodon/mastodon/releases/tag/v4.4.19",
      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/mastodon/mastodon/releases/tag/v4.5.12",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/mastodon/mastodon/security/advisories/GHSA-3rhr-8phh-jm86",
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "lastModified": "2026-09-16T13:42:44.293",
  "sourceIdentifier": "security-advisories@github.com"
}