CVE-2026-24044CWE-336

ESS Community Helm Chart has a weak server key generation method

Critical · published February 12, 2026

CVSS v4.0
9.2
EPSS
0%
Percentile
19.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.2 · CRITICAL
Vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS
0.00278 · 19.9th percentile
Weakness
CWE-336 · Same Seed in Pseudo-Random Number Generator (PRNG)
Published
2026-02-12T19:06Z
EPSS history
Timeline
  • 12 FEB 19:06Z
    ESS Community Helm Chart has a weak server key generation method
    cvelistv5