Taskcluster: Unauthenticated remote code execution in `web-server` via GraphQL `filter` argument (sift `$where`)
Priority MEDIUM 44CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Privilege escalation, Security bypass, Code execution
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-250, CWE-306 and CWE-94.
Summary
Taskcluster is the task execution framework that supports Mozilla's continuous integration and release processes. Prior to version 100.3.0, Taskcluster is vulnerable to unauthenticated RCE on Taskcluster deployments with an anonymous role that exposes the GraphQL endpoint and parses filter arguments using the sift library. This issue has been patched in version 100.3.0.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00423 36th percentileScored 2026-11-07
Fix Fixed taskcluster (taskcluster): 100.3.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| taskcluster | taskcluster | before 100.3.0 | 100.3.0 | Patch available | CNA |
- taskcluster Vendortaskcluster Affected before 100.3.0 Fixed in 100.3.0 Patch available CNA
Remediation
- Fix · CNA taskcluster (taskcluster) Fixed in 100.3.0
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-55094
- 2026-10-03 Alias added: GHSA-v484-996h-6h4h
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
Other 6
- https://github.com/taskcluster/taskcluster/security/advisories/GHSA-ccv5-c45x-2q38
- https://github.com/taskcluster/taskcluster/issues/8716
- https://github.com/taskcluster/taskcluster/pull/8718
- https://github.com/taskcluster/taskcluster/commit/a1b0154b8235937657c2ded127f193b564e2334b
- https://bugzilla.mozilla.org/show_bug.cgi?id=2045091
- https://github.com/taskcluster/taskcluster/releases/tag/v100.3.0
Sources
- CVE-2026-55094 · CVE Program
- CVE-2026-55094 · NVD
- FIRST EPSS
- GHSA-v484-996h-6h4h · GitHub Advisory Database · CC BY 4.0
- CVE-2026-55094 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences