CVE-2026-55867
Fix: Graylog2/graylog2-server#26049CVE-2026-55867 is a CWE-639 vulnerability in org.graylog2:graylog2-server. O3 Security confirms whether CVE-2026-55867 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Graylog token revocation endpoint allows authenticated users to delete other users’ access tokens
Real-World Exposure
org.graylog2:graylog2-server☕org.graylog2:graylog2-server☕org.graylog2:graylog2-serverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Graylog contains an insecure direct object reference (IDOR) vulnerability in the token revocation endpoint. An authenticated user can delete access tokens belonging to other users, including service account tokens and administrator tokens, if they know or can guess a valid token identifier.
The issue does not expose token contents, but it allows unauthorized token deletion, leading to integrity impact and potential availability impact for access token based integrations.
Patches
The issue has been fixed in the following Graylog versions: 6.3.12, 7.0.7, 7.1.2. Users should upgrade to one of these versions or above to remediate the vulnerability.
Graylog Cloud has already been patched.
Workarounds
There are no feasible workarounds for this issue. Upgrading to a patched version is recommended.
Customers using Graylog Enterprise or Security can review the audit log1 for suspicious activity. Audit log lines for successful token deletions begin with access token deleted from user.
Credits
Thanks to michaelddickenson and sreelim for reporting.
Footnotes
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.graylog2:graylog2-server | ≥ 6.2.0&&< 6.3.12 | 6.3.12 |
| ☕Maven | org.graylog2:graylog2-server | ≥ 7.0.0&&< 7.0.7 | 7.0.7 |
| ☕Maven | org.graylog2:graylog2-server | ≥ 7.1.0&&< 7.1.2 | 7.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.graylog2:graylog2-server. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.graylog2:graylog2-server to 6.3.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55867 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55867 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-55867. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55867 in your dependencies?
O3 detects CVE-2026-55867 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.