ESS Community Helm Chart has a weak server key generation method
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
Element Server Suite Community Edition (ESS Community) deploys a Matrix stack using the provided Helm charts and Kubernetes distribution. The ESS Community Helm Chart secrets initialization hook (using matrix-tools container before 0.5.7) is using an insecure Matrix server key generation method, allowing network attackers to potentially recreate the same key pair, allowing them to impersonate the victim server. The secret is generated by the secrets initialization hook, in the ESS Community Helm Chart values, if both initSecrets.enabled is not set to false and synapse.signingKey is not defined. Given a server key in Matrix authenticates both requests originating from and events constructed on a given server, this potentially impacts confidentiality, integrity and availability of rooms which have a vulnerable server present as a member. The confidentiality of past conversations in end-to-end encrypted rooms is not impacted. The key generation issue was fixed in matrix-tools 0.5.7, released as part of ESS Community Helm Chart 25.12.1.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
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 |
|---|---|---|---|---|---|
| element-hq | ess-helm | before 25.12.1 | 25.12.1 | Patch available | CNA |
| element-hq | matrix-tools | before 0.5.7 | 0.5.7 | Patch available | CNA |
- ess-helm Vendorelement-hq Affected before 25.12.1 Fixed in 25.12.1 Patch available CNA
- matrix-tools Vendorelement-hq Affected before 0.5.7 Fixed in 0.5.7 Patch available CNA
Remediation
- Fix · CNA ess-helm (element-hq) Fixed in 25.12.1
- Fix · CNA matrix-tools (element-hq) Fixed in 0.5.7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-24044
References
More element-hq vulnerabilities
- TI-2024-35327 Synapse allows a a malformed invite to break the invitee's `/sync` CVSS 4.0HIGH 8.7
- TI-2024-36056 Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders CVSS 4.0HIGH 8.2
- TI-2024-35318 Synapse allows unsupported content types to lead to memory exhaustion CVSS 4.0HIGH 8.2
- TI-2022-07650 Remote program execution with user interaction CVSS 3.1HIGH 8.8
- TI-2024-24814 Synapse denial of service through media disk space consumption CVSS 3.1HIGH 7.5
- TI-2026-35452 Element Call reports full URLs of visited pages to analytics server CVSS 4.0HIGH 8.6
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences