CVE-2026-89139Network attack vectorHinoki check available

Authenticated host command execution via subprocess provider

Published Sep 21, 2026 · Updated Sep 21, 2026

OS command injection in Temporal Server 1.31.0 through 1.31.2 allows remote authenticated users to execute commands on the Worker Service host. The Worker Controller subprocess provider passes a request-supplied program and argument vector to a host process, while an unset provider allowlist permits the provider by default. A namespace write role, registered worker deployment, running Worker Service, and configured authorization suffice; execution uses the server account and exposes cluster-wide persistence credentials and TLS material.

CVSS severity8.7
High
EPSS probability0.58%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

OS command injection in Temporal Server 1.31.0 through 1.31.2 allows remote authenticated users to execute commands on the Worker Service host. The Worker Controller subprocess provider passes a request-supplied program and argument vector to a host process, while an unset provider allowlist permits the provider by default. A namespace write role, registered worker deployment, running Worker Service, and configured authorization suffice; execution uses the server account and exposes cluster-wide persistence credentials and TLS material.

The record

CVE
CVE-2026-89139
Published
Sep 21, 2026
Updated
Sep 21, 2026
Vendor
Temporal Technologies
Product
Temporal Server
Classifications
CWE-78, CWE-1188, CWE-749, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.31.0 <1.31.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Temporal Technologies · Temporal Serverversion=1.31.0 <1.31.3

Published CVSS scores

8.7Temporal TechnologiesCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE-1188Initialization of a Resource with an Insecure Default
CWE-749Exposed Dangerous Method or Function
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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