Apache Pulsar: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-105945 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in Apache Pulsar from Apache, with a CVSS 4.0 base score of 7.7 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 0.49% 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 | 2.10.0 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
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious 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)
- LowLimited loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- LowLimited loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/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:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (apache.org).
Official description
The Pulsar Packages Management Service can be configured to store packages on the local filesystem of the broker by using the filesystem storage provider. Package names consist of a type, tenant, namespace, name and version. Authorization of package operations is based only on the tenant and namespace, while the storage location of a package is derived from all of these components. The version component of a package name was not validated, so it could contain URL-encoded path separators and parent directory references. The filesystem storage provider resolved such a version to a location belonging to a package in a different tenant or namespace. Because that location is inside the configured storage directory, the containment check that the filesystem storage provider performs in recent releases did not prevent the access. An authenticated user who has the packages permission on any namespace could use this to download, overwrite or delete packages stored in other tenants or namespaces for which the user has no permission. Packages overwritten or deleted in this way may be used by Pulsar Functions, Sources or Sinks, so the issue can affect the integrity and availability of these components. If authentication is disabled, the operations are available to any client that can reach the broker's admin REST API. This issue only affects deployments in which package management is enabled with the broker setting enablePackagesManagement and the filesystem storage provider (FileSystemPackagesStorageProvider) is configured with the setting packagesManagementStorageProvider. Package management is disabled by default, and the default storage provider, which stores packages in Apache BookKeeper, is not affected. This issue affects Apache Pulsar versions from 2.10.0 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/.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Apache Pulsar
- 7.7 High severity
- 8.7 High severity
- 7.2 High severity
- 9.2 Critical severity
- 8.8 High severity
- 9.9 Critical severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 8.8 High severity
- 8.7 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
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