CVE-2026-5199
Detail
Awaiting Enrichment
This CVE record has been marked for NVD enrichment efforts.
Description
A writer role user in an attacker-controlled namespace could signal, delete, and reset workflows or activities in a victim namespace on the same cluster. Exploitation requires the attacker to know or guess specific victim workflow ID(s) and, for signal operations, signal names. This was due to a bug introduced in Temporal Server v1.29.0 which inadvertently allowed an attacker to control the namespace name value instead of using the server's own trusted name value within the batch activity code. The batch activity validated the namespace ID but did not cross-check the namespace name against the worker's bound namespace, allowing the per-namespace worker's privileged credentials to operate on an arbitrary namespace. Exploitation requires a server configuration where internal components have cross-namespace authorization, such as deployment of the internal-frontend service or equivalent TLS-based authorization for internal identities.
This vulnerability also impacted Temporal Cloud when the attacker and victim namespaces were on the same cell, with the same preconditions as self-hosted clusters.
Metrics
NVD enrichment efforts reference publicly available information to associate
vector strings. CVSS information contributed by other sources is also
displayed.
CVSS 4.0 Severity and Vector Strings:
NVD assessment
not yet provided.
CNA: Temporal Technologies Inc.
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L/S:N/AU:Y/R:U/RE:M
CVSS 3.x Severity and Vector Strings:
Base
Score:
NVD assessment
not yet provided.
CVSS 2.0 Severity and Vector Strings:
Base
Score:
NVD assessment
not yet provided.
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Weakness Enumeration
| CWE-ID |
CWE Name |
Source |
|
CWE-639
|
Authorization Bypass Through User-Controlled Key |
Temporal Technologies Inc.
|
Change History
3 change records found show changes
CVE Modified by CISA-ADP
6/17/2026 6:58:35 AM
| Action |
Type |
Old Value |
New Value |
| Added |
SSVC |
{"timestamp":"2026-04-01T18:23:18.346230Z","id":"CVE-2026-5199","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}
|
CVE Modified by Temporal Technologies Inc.
6/17/2026 6:58:35 AM
| Action |
Type |
Old Value |
New Value |
| Added |
Affected |
[{"vendor":"Temporal Technologies, Inc.","product":"temporal","defaultStatus":"unaffected","packageName":"temporal","modules":["Batch Operations"],"repo":"https://github.com/temporalio/temporal","versions":[{"version":"1.29.0","lessThan":"1.29.5","versionType":"semver","status":"affected"},{"version":"1.30.0","lessThan":"1.30.3","versionType":"semver","status":"affected"}]}]
|
New CVE Received from Temporal Technologies Inc.
4/01/2026 2:16:31 PM
| Action |
Type |
Old Value |
New Value |
| Added |
Description |
A writer role user in an attacker-controlled namespace could signal, delete, and reset workflows or activities in a victim namespace on the same cluster. Exploitation requires the attacker to know or guess specific victim workflow ID(s) and, for signal operations, signal names. This was due to a bug introduced in Temporal Server v1.29.0 which inadvertently allowed an attacker to control the namespace name value instead of using the server's own trusted name value within the batch activity code. The batch activity validated the namespace ID but did not cross-check the namespace name against the worker's bound namespace, allowing the per-namespace worker's privileged credentials to operate on an arbitrary namespace. Exploitation requires a server configuration where internal components have cross-namespace authorization, such as deployment of the internal-frontend service or equivalent TLS-based authorization for internal identities.
This vulnerability also impacted Temporal Cloud when the attacker and victim namespaces were on the same cell, with the same preconditions as self-hosted clusters.
|
| Added |
CVSS V4.0 |
AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L/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:N/AU:Y/R:U/V:X/RE:M/U:X
|
| Added |
CWE |
CWE-639
|
| Added |
Reference |
https://github.com/temporalio/temporal/releases/tag/v1.29.5
|
| Added |
Reference |
https://github.com/temporalio/temporal/releases/tag/v1.30.3
|
Quick Info
CVE Dictionary Entry: CVE-2026-5199 NVD
Published Date: 04/01/2026 NVD
Last Modified: 06/17/2026
Source: Temporal Technologies Inc.
|
