CVE-2026-108126 Temporal Technologies, Inc. CVE debrief

Who should care

Defenders responsible for Temporal server deployments using temporal-proxy versions 0.2.0 through 0.8.0 should assess exposure and prioritize upgrading to version 0.9.0 or later. This includes reviewing namespace configurations for potential exposure and monitoring for suspicious decryption requests. Defenders should also verify and upgrade to temporal-proxy version 0.9.0 or later, and review compensating controls for exposed systems while remediation is

Why it matters

CVE-2026-108126 allows unauthorized decryption of encrypted payloads in temporal-proxy versions 0.2.0 through 0.8.0, impacting defenders responsible for Temporal server deployments.

• Potential unauthorized decryption of encrypted payloads
• Possible exposure of sensitive data
• Need for verification of namespace configurations
• Priority for upgrading to temporal-proxy version 0.9.0 or later

Technical summary

The temporal-proxy versions 0.2.0 through 0.8.0 do not bind encrypted payloads to the namespace they were encrypted for, allowing a caller authorized only for namespace B to have the proxy decrypt a payload from namespace A. This issue allows unauthorized decryption of encrypted payloads, impacting defenders responsible for Temporal server deployments. The vulnerability is caused by the proxy choosing the decryption key by an identifier stored in the payload rather than by the namespace of the request, and nothing in the ciphertext records that namespace.

Defensive priority

Defenders should prioritize verifying and upgrading to temporal-proxy version 0.9.0 or later, and review namespace configurations for potential exposure.

Recommended defensive actions

• Verify and upgrade to temporal-proxy version 0.9.0 or later
• Review namespace configurations for potential exposure
• Monitor for suspicious decryption requests
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The CVE record and source item provide details on the vulnerability in temporal-proxy versions 0.2.0 through 0.8.0, where encrypted payloads are not bound to the request namespace, allowing for potential decryption by unauthorized callers.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.