CyberSecBulletin
CVE-2026-104355NVD status: Awaiting Analysis

Temporal Server: Incorrect Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-104355 is a high-severity incorrect authorization vulnerability in Temporal Server from Temporal Technologies, with a CVSS 4.0 base score of 7.0 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists versions 1.30.8, 1.31.4, 1.32.1 as the first without the flaw, so updating Temporal Server to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Temporal Server to 1.30.8 or 1.31.4 or 1.32.1, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
Temporal TechnologiesTemporal Server1.0.0 through 1.29.7; 1.30.0 up to, but not including, 1.30.8; 1.31.0 up to, but not including, 1.31.4; 1.32.0 up to, but not including, 1.32.11.30.8, 1.31.4, 1.32.1

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
NoneNo loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
LowLimited loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/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. Scored by CNA (temporal.io).

Official description

A connected peer cluster can modify a Temporal Server cluster's local namespaces, which are never replicated to that peer, because the receiving cluster applies inbound namespace replication updates to them. In a multi-cluster deployment, each cluster pulls replication tasks from the remote clusters an administrator has registered with connection enabled; the sending side excludes local namespaces, but the receiving side does not apply the same rule. When an inbound task names an existing namespace, the server checks at most that the namespace identifiers match, then overwrites its state, description, owner, retention, archival settings, and cluster list, and its active cluster when the task carries a higher failover version, without checking that the namespace is global. A party that controls a registered peer's replies, by operating or compromising it, can therefore change any local namespace whose name and identifier it can supply, without any credential on the receiving cluster: for example, marking it Deprecated, making the peer its active cluster, and shortening its retention, after which new Workflow starts in that namespace fail. Local namespaces include the built-in temporal-system namespace. Namespace metadata the History service refreshes from the peer while processing its history replication tasks passes through the same logic. A cluster with no remote cluster registered with connection enabled is not exposed.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

How developers prevent this class of flaw

  • Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.

More Incorrect Authorization vulnerabilities (CWE-863)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Temporal Server

All Temporal Server vulnerabilities

Recent Incorrect Authorization vulnerabilities

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