CVE-2026-108126
Received Received - Intake

temporal-proxy Namespace Bypass via Payload Decryption

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: Temporal Technologies Inc.

Description
temporal-proxy 0.2.0 through 0.8.0 does not bind encrypted payloads to the namespace they were encrypted for. When payload encryption is enabled, the proxy chooses 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. A caller whom the proxy authorizes only for namespace B, and who has obtained an encrypted payload from namespace A, can therefore have the proxy decrypt it. In 0.8.0, the caller can submit the payload to the codec server's /decode endpoint. In every affected version, a caller who can also write to namespace B on the Temporal server directly can place the payload there and read it back through the proxy. This holds whether namespaces share the default key or each has its own, because a single proxy holds every key it is configured with. The issue does not give the attacker encrypted payloads they could not already obtain, and does not allow encrypted payloads to be modified.

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-16
AI Q&A
2026-10-15
EPSS Evaluated
N/A
NVD
CVE-2026-108126
EUVD
EUVD-2026-102301

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
Temporal Technologies, Inc. temporal-proxy 0.2.0

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-639 The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

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Executive Summary

The vulnerability in temporal-proxy versions 0.2.0 through 0.8.0 involves improper binding of encrypted payloads to their intended namespaces. When payload encryption is enabled, the proxy decrypts payloads using a key identifier from the payload itself rather than the namespace of the request. This allows an attacker authorized only for namespace B to decrypt payloads encrypted for namespace A if they can access namespace B on the Temporal server. The issue does not allow modification of encrypted payloads or creation of new ones.

Detection Guidance

To detect this vulnerability, check if your temporal-proxy version is between 0.2.0 and 0.8.0. Run: temporal-proxy version. If vulnerable, inspect payload decryption logs for namespace mismatches or unauthorized decryptions. Enable namespace binding metrics: vault_unbound_opens_total and vault_namespace_mismatches_total.

Impact Analysis

If you use temporal-proxy versions 0.2.0 through 0.8.0 with payload encryption enabled, an attacker with access to one namespace could decrypt payloads intended for another namespace. This could lead to unauthorized access to sensitive data if namespaces share the same encryption keys or if the attacker can write to the target namespace.

Compliance Impact

This vulnerability could violate compliance requirements that mandate strict data isolation between namespaces or tenants, such as GDPR's data separation principles or HIPAA's access controls. Unauthorized decryption of cross-namespace payloads may result in unauthorized data exposure, potentially leading to regulatory penalties or breaches of confidentiality.

Mitigation Strategies

Upgrade temporal-proxy to version 0.9.0 or later. Enable namespace binding in strict mode via encryption.namespaceBinding=strict. Monitor metrics vault_unbound_opens_total and vault_namespace_mismatches_total to ensure proper enforcement.

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