temporal-proxy payload decryption is not bound to the request namespace
Summary
| CVE | CVE-2026-108126 |
|---|---|
| State | PUBLISHED |
| Assigner | Temporal |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-15 19:17:19 UTC |
| Updated | 2026-10-16 19:55:59 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 6 MEDIUM from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.003560000 probability, percentile 0.277430000 (date 2026-10-16)
Problem Types: CWE-639 | CWE-639 CWE-639: Authorization Bypass Through User-Controlled Key
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 6 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Temporal Technologies Inc. | Temporal-proxy | affected 0.2.0 0.9.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/vault.go | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/kek.go | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/pull/221 | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/discussions/146 | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/releases/tag/v0.9.0 | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/pull/222 | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/commit/508991c298b9ac31915dd7349ffa... | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/dek.go | [email protected] | github.com | |
| github.com/temporalio/temporal-proxy/commit/6843a2c4626aa2c7f00fbf54e4e9... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Reported internally at Temporal Technologies, Inc. (en)
CNA: Praetorian, who independently reported this issue responsibly to Temporal Technologies (en)
Additional Advisory Data
Solutions
CNA: Upgrade to temporal-proxy 0.9.0 or later and set encryption.namespaceBinding to strict. Fixed releases record the namespace in each payload they encrypt and, in strict mode, refuse to decrypt a payload recorded for another namespace or for none, including through the codec server's /decode endpoint, which then requires the caller to name a namespace. The setting has no default and must be set whenever encryption keys are configured. The off and permissive modes exist to migrate payloads encrypted by earlier releases, which carry no namespace, and do not close this issue; move to strict once the vault_unbound_opens_total and vault_namespace_mismatches_total metrics have stayed at zero for longer than namespace retention. Payloads carried in Nexus operations are not compared, because they cross namespaces by design.
Workarounds
CNA: Until a fixed release is deployed, serve namespaces that must stay isolated from each other through separate proxy deployments, or use KMS key policies that let each proxy use only the keys of the namespaces it serves. Giving each namespace its own key on a single proxy does not help, because that proxy holds all of them. Leaving the codec server disabled closes the /decode route only.