High

Flarum < 1.8.16 Session Persistence via Improper Access Token Revocation

Type: advisorySources: OSV

Flarum before 1.8.16 contains an improper session invalidation vulnerability that allows attackers who hold a valid session token to retain full account access after a victim changes their password, because the access_tokens table is never cleared on password change events. The TokensClearer::clearPasswordTokens() function only removes rows from the password_tokens table while leaving all active session cookies and API bearer tokens intact, including long-lived RememberAccessToken entries, and administrator-forced password resets via the user update endpoint are equally ineffective at revoking attacker-held sessions.

Products: Not specified
Affected versions: Not specified
Fixed versions: Not specified
CVEs: CVE-2026-39924
Confirmed fixed CVEs: Not specified
Updated in this feed: 4 Nov 2026, 02:35 UTC · Revision 1

Source evidence

Flarum < 1.8.16 Session Persistence via Improper Access Token Revocation

core-osv · Original source

Published 5 Aug 2026, 14:40 UTC

osv:CVE-2026-39924

Complete source record

{
  "id": "c436b0c072faac09f6b57854fa406e486a1175258ac0423a8a1df0d1bb41cf3c",
  "url": "https://osv.dev/vulnerability/CVE-2026-39924",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Flarum < 1.8.16 Session Persistence via Improper Access Token Revocation",
    "summary": "Flarum before 1.8.16 contains an improper session invalidation vulnerability that allows attackers who hold a valid session token to retain full account access after a victim changes their password, because the access_tokens table is never cleared on password change events. The TokensClearer::clearPasswordTokens() function only removes rows from the password_tokens table while leaving all active session cookies and API bearer tokens intact, including long-lived RememberAccessToken entries, and administrator-forced password resets via the user update endpoint are equally ineffective at revoking attacker-held sessions.",
    "evidence": "osv:CVE-2026-39924",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-39924",
      "aliases": [
        "CVE-2026-39924"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/flarum/framework",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "a2260e4a62f21591e1a9ae9b11c7db07c6507766"
                },
                {
                  "fixed": "5f080293a029d0d273eb9678d597c74ea86a3bcc"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.8.16"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a2260e4a62f21591e1a9ae9b11c7db07c6507766"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.8.16"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5f080293a029d0d273eb9678d597c74ea86a3bcc"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.8.15",
            "v1.8.14",
            "v1.8.13",
            "v1.8.12",
            "v1.8.11",
            "v1.8.10",
            "v1.8.9",
            "v1.8.8",
            "v1.8.7",
            "v1.8.6",
            "v1.8.5",
            "v1.8.3",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "v1.7.1",
            "v1.7.0",
            "v1.6.1",
            "v1.6.0",
            "v1.5.0",
            "v1.4.0",
            "v1.3.1",
            "v1.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39924.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.614329248Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39924.json",
        "https://github.com/flarum/framework/releases/tag/v1.8.16",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-39924",
        "https://www.vulncheck.com/advisories/flarum-session-persistence-via-improper-access-token-revocation",
        "https://github.com/flarum/framework/pull/4546",
        "https://github.com/flarum/framework/commit/5f080293a029d0d273eb9678d597c74ea86a3bcc",
        "https://github.com/flarum/framework"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-613"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39924.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-39924",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499717,
  "published_at": "2026-08-05T14:40:27.741+00:00"
}