MediumCVE-2026-108126

    temporal-proxy payload decryption is not bound to the request namespace (CVE-2026-108126)

    Published Last modified Sources: CVE.org

    What is affected, what to do

    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.

    Update Temporal Technologies Temporal-proxy to version 0.9.0.

    Affected
    • Temporal Technologies Temporal-proxy lt 0.2.0..0.9.0
    Fixed in
    • Temporal Technologies Temporal-proxy 0.9.0

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    6.0

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    6.0

    CVSS v4

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 29.2

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    66.83 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    6.0 Methodology
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    6.0
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    0.4 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    29.2
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 15 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-639

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    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.

    Source: cvelistv5, NVD (NIST)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    Temporal Technologies, Inc.temporal-proxy
    • 0.2.0 – < 0.9.0
    • 0.9.0

    Vendors and products

    Weakness classes (CWE)

    • CWE-639Authorization Bypass Through User-Controlled Key

      Base

      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.

      Entry at MITRE CWE-639

    References & sources

    • github.comVault.Open in temporal-proxy 0.8.0, which takes no namespaceProduct
    • github.comKEKRegistry.Decrypt in temporal-proxy 0.8.0, which selects the KEK by the identifier in the payloadProduct
    • github.comAES-256-GCM sealed and opened with no associated data in temporal-proxy 0.8.0Product
    • github.comDesign discussion of associated data in the payload encryption schemeTechnical description
    • github.comFix pull requestPatch
    • github.comFix commitPatch
    • github.comCodec server fix pull requestPatch
    • github.comCodec server fix commitPatch
    • github.comtemporal-proxy 0.9.0Release notes

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-108126","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-15T20:04:10.335323Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Receivedtemporal.io

      CVSS V4.0: AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

      Weakness type: CWE-639

      Description added or changed

      Show 13 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      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.
      CVSSadded
      —
      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
      Weakness type (CWE)added
      —
      CWE-639
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/108xxx/CVE-2026-108126.json">CVE-2026-108126</a>
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/dek.go#L54-L67
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/kek.go#L172-L180
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/blob/v0.8.0/pkg/crypto/vault.go#L256
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/commit/508991c298b9ac31915dd7349ffa88d79fad3475
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/commit/6843a2c4626aa2c7f00fbf54e4e9fa98f6254f07
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/discussions/146
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/pull/221
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/pull/222
      Referenceadded
      —
      https://github.com/temporalio/temporal-proxy/releases/tag/v0.9.0

      Source identifier: security@temporal.io

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