All published s2s-proxy versions through 0.2.2 are affected. In versions 0.1.16 through 0.2.2, TLS server listeners use Go's RequireAnyClientCert mode when skipCAVerification is false. This mode checks that the client holds the certificate's private key but does not verify the certificate against the configured CA. An attacker can therefore use a self-signed certificate and key to establish a TLS and yamux connection, then invoke RPCs allowed by the proxy's configuration and Temporal credentials. No certificate or private key trusted by the deployment, and no Temporal credential, is required.
Metrics
Affected Vendors & Products
References
History
Thu, 24 Sep 2026 09:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Temporal Technologies, Inc.
Temporal Technologies, Inc. s2s-proxy |
|
| Vendors & Products |
Temporal Technologies, Inc.
Temporal Technologies, Inc. s2s-proxy |
Wed, 23 Sep 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 23 Sep 2026 19:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | All published s2s-proxy versions through 0.2.2 are affected. In versions 0.1.16 through 0.2.2, TLS server listeners use Go's RequireAnyClientCert mode when skipCAVerification is false. This mode checks that the client holds the certificate's private key but does not verify the certificate against the configured CA. An attacker can therefore use a self-signed certificate and key to establish a TLS and yamux connection, then invoke RPCs allowed by the proxy's configuration and Temporal credentials. No certificate or private key trusted by the deployment, and no Temporal credential, is required. | |
| Title | s2s-proxy accepts untrusted client certificates | |
| Weaknesses | CWE-296 | |
| References |
|
|
| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: Temporal
Published: 2026-09-23T18:58:46.233Z
Updated: 2026-09-23T19:36:12.488Z
Reserved: 2026-09-23T16:06:36.077Z
Link: CVE-2026-96770
Updated: 2026-09-23T19:36:10.230Z
Status : Deferred
Published: 2026-09-23T19:19:55.013
Modified: 2026-09-24T20:43:32.537
Link: CVE-2026-96770
No data.