01 Record

CVE-2026-89139

Temporal Server worker deployment compute provider executes a caller-supplied command on the Worker Service host

HighPUBLISHEDCNA: Temporal

CNA base score8.7 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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02 Description

Temporal Server worker deployment compute provider executes a caller-supplied command on the Worker Service host

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.58% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 47.4% of scored records. A rank, not a probability.

NVD base score

8.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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

NVD analysis status

Awaiting Analysis. NVD last modified this record on 2026-09-22.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2026-09-21 11:41Z1 MO AGO

Last updated

2026-09-21 15:24Z1 MO AGO

Reserved

2026-09-10

Assigning CNA

Temporal

Record state

PUBLISHED

Severity

High (CVSS 8.7)

CNA CVSS vector

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

Weaknesses

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')Base
CWE-749Exposed Dangerous Method or FunctionBase
CWE-1188Initialization of a Resource with an Insecure DefaultBase

Data version

5.2

Document digest

41d5f47d5fb36726e4d10a01efea21fee0105c29be2164dde201176f1a7f1590

05 Affected products

VendorProductVersionsPlatforms

Temporal Technologies, Inc.Temporal Server1.31.0 to < 1.31.3—

06 References

github.comFirst fixed releasehttps://github.com/temporalio/temporal/releases/tag/v1.32.0release-notes
github.comTemporal Server 1.31.3, first fixed 1.31 releasehttps://github.com/temporalio/temporal/releases/tag/v1.31.3release-notes
github.comFix pull request, compute provider allowlist changed to deny by defaulthttps://github.com/temporalio/temporal-auto-scaled-workers/pull/129patch
github.comModule bump carrying the fix into the Temporal Server 1.32 release branchhttps://github.com/temporalio/temporal/pull/12021patch

07 Remediation

Upgrade to Temporal Server 1.32.0 or 1.31.3. Both pin a Worker Controller Instance module revision whose compute provider allowlist denies by default instead of permitting every registered provider. Operators who cannot upgrade immediately can apply the workaround below, which closes the same path without waiting for a release. The 1.30 release line does not depend on the Worker Controller Instance module at all and is unaffected. Note that the change shipped in 1.32.0 and 1.31.3 makes the allowlist deny by default and does not change where the executed command comes from: for a compute provider an operator does deliberately add to the allowlist, the program name and argument vector still arrive in the caller's request.