Apache Pulsar: Missing Authorization
CVE-2026-105934 is a high-severity missing authorization vulnerability in Apache Pulsar from Apache, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 4.0.14, 4.2.5 as the first without the flaw, so updating Apache Pulsar to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.48% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache Pulsar to 4.0.14 or 4.2.5, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Pulsar | 2.8.0 up to, but not including, 4.0.14; 4.1.0 up to, but not including, 4.2.5 | 4.0.14, 4.2.5 |
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
- LowA basic user account is enough.
- 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)
- HighSerious 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:L/UI:N/VC:N/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. Scored by CNA (apache.org).
Official description
The Apache Pulsar broker admin REST API provides a truncate operation for persistent topics (DELETE /admin/v2/persistent/{tenant}/{namespace}/{topic}/truncate). Truncating a topic moves all subscription cursors of the topic to the end of the topic and deletes the topic's inactive ledgers. Truncating a non-partitioned topic, or a single partition addressed by its partition name, correctly requires the tenant admin role or the superuser role. When the operation is requested for the name of a partitioned topic, the broker does not apply this tenant admin check to the caller. Instead, it truncates each partition using the broker's own internal admin client, which authenticates with the broker's configured client credentials rather than the caller's identity. Each per-partition truncate request is still checked for the tenant admin role or the superuser role, but against the broker's internal identity instead of the caller. The partitions are therefore truncated only when the broker's configured client role is a superuser or an admin of the target tenant, which is the usual configuration when authorization is enabled. As a result, when that condition holds, an authenticated user who is not a tenant admin can truncate any partitioned topic on which the user has lookup permission. Caller authentication and lookup permission alone are not sufficient: if the broker's internal identity lacks tenant admin or superuser authorization for the target tenant, the per-partition requests are rejected. With the default authorization provider, lookup permission is granted by produce or consume permission on the topic or its namespace. A user with no permissions on the topic cannot trigger the issue. This impact analysis assumes that Pulsar has been configured with the default authorization provider. For custom authorization providers, the impact could be different. Truncating a partitioned topic this way moves the cursors of all subscriptions on every partition to the end of the topic, so any unacknowledged backlog is skipped and is no longer delivered to consumers. It also deletes eligible older ledgers of each partition regardless of the namespace's configured retention policy, so messages stored in those ledgers can be permanently lost. The ledger currently being written is not deleted by the truncate operation. The issue does not allow reading message contents or changing permissions or configuration, and it does not give access to topics on which the user has no lookup permission. This issue affects Apache Pulsar versions from 2.8.0 before 4.0.14 and from 4.1.0 before 4.2.5. - 4.0.x version users should upgrade to at least 4.0.14. - 4.1.x and 4.2.x version users should upgrade to at least 4.2.5. Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions. The currently supported Apache Pulsar release lines are 4.0.x and 5.0.x. The supported versions schedule is available at https://pulsar.apache.org/contribute/release-policy/. Users who cannot upgrade immediately can reduce exposure by restricting network access to the broker's admin REST API (/admin/v2) to trusted administrative clients.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Apache Pulsar
- 7.7 High severity
- 7.7 High severity
- 8.7 High severity
- 9.2 Critical severity
- 8.8 High severity
- 9.9 Critical severity
Recent Missing Authorization vulnerabilities
- 8.8 High severity
- 7.3 High severity
- 8.1 High severity
- 7.1 High severity
- 8.8 High severity
- 8.2 High severity
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