Node-Tar <7.5.4 Race Condition Enables Symlink Poisoning on APFS
CVE-2026-23950 Published on January 20, 2026

node-tar has Race Condition in Path Reservations via Unicode Ligature Collisions on macOS APFS
node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3. This is due to an incomplete handling of Unicode path collisions in the `path-reservations` system. On case-insensitive or normalization-insensitive filesystems (such as macOS APFS, In which it has been tested), the library fails to lock colliding paths (e.g., `ß` and `ss`), allowing them to be processed in parallel. This bypasses the library's internal concurrency safeguards and permits Symlink Poisoning attacks via race conditions. The library uses a `PathReservations` system to ensure that metadata checks and file operations for the same path are serialized. This prevents race conditions where one entry might clobber another concurrently. This is a Race Condition which enables Arbitrary File Overwrite. This vulnerability affects users and systems using node-tar on macOS (APFS/HFS+). Because of using `NFD` Unicode normalization (in which `ß` and `ss` are different), conflicting paths do not have their order properly preserved under filesystems that ignore Unicode normalization (e.g., APFS (in which `ß` causes an inode collision with `ss`)). This enables an attacker to circumvent internal parallelization locks (`PathReservations`) using conflicting filenames within a malicious tar archive. The patch in version 7.5.4 updates `path-reservations.js` to use a normalization form that matches the target filesystem's behavior (e.g., `NFKD`), followed by first `toLocaleLowerCase('en')` and then `toLocaleUpperCase('en')`. As a workaround, users who cannot upgrade promptly, and who are programmatically using `node-tar` to extract arbitrary tarball data should filter out all `SymbolicLink` entries (as npm does) to defend against arbitrary file writes via this file system entry name collision issue.

Github Repository NVD

Vulnerability Analysis

CVE-2026-23950 is exploitable with network access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a high impact on integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
CHANGED
Confidentiality Impact:
LOW
Integrity Impact:
HIGH
Availability Impact:
LOW

Weakness Types

Improper Handling of Unicode Encoding

The software does not properly handle when an input contains Unicode encoding.

What is a Session Riding Vulnerability?

The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request. When a web server is designed to receive a request from a client without any mechanism for verifying that it was intentionally sent, then it might be possible for an attacker to trick a client into making an unintentional request to the web server which will be treated as an authentic request. This can be done via a URL, image load, XMLHttpRequest, etc. and can result in exposure of data or unintended code execution.

CVE-2026-23950 has been classified to as a Session Riding vulnerability or weakness.

What is a TOCTTOU Vulnerability?

The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.

CVE-2026-23950 has been classified to as a TOCTTOU vulnerability or weakness.


Products Associated with CVE-2026-23950

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Red Hat Enterprise Linux (RHEL)
 
Red Hat Openshift Devspaces
 
Red Hat Trusted Artifact Signer
 
Red Hat Confidential Compute Attestation
 
Red Hat Logging
 
Red Hat Rhmt
 
Red Hat Network Observ Optr
 
Red Hat Openshift Lightspeed
 
Red Hat Openshift Pipelines
 
Red Hat Serverless
 
Red Hat 3scale Amp
 
Red Hat Connectivity Link
 
Red Hat Rhdh
 
Red Hat Enterprise Linux Ai
 
Red Hat Jboss Fuse
 
Red Hat Openshift Ai
 
Red Hat Openshift
 
Red Hat Openshift Data Foundation
 
Red Hat Openshift Gitops
 
Red Hat Satellite
 
Red Hat Cryostat
 
Red Hat Multicluster Engine
 
Red Hat Workload Availability Nhc
 
Red Hat Acm
 
Red Hat Amq Broker
 
Red Hat Ansible Automation Platform
 
Red Hat Apache Camel Hawtio
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Jbosseapxp
 
Red Hat Jboss Enterprise Bpms Platform
 
Red Hat Quay
 
Red Hat Single Sign On
 

Affected Versions

isaacs node-tar: Red Hat Enterprise Linux AppStream (v. 10): Red Hat Enterprise Linux AppStream (v. 9): Red Hat OpenShift Dev Spaces 3.27: Red Hat Trusted Artifact Signer 1.2: Red Hat Trusted Artifact Signer 1.3: Red Hat Confidential Compute Attestation: Logging Subsystem for Red Hat OpenShift: Red Hat Migration Toolkit for Containers: Red Hat Network Observability Operator: Red Hat OpenShift Lightspeed: Red Hat OpenShift Pipelines: Red Hat OpenShift Serverless: Red Hat 3scale API Management Platform 2: Red Hat Connectivity Link 1: Red Hat Developer Hub: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux AI (RHEL AI) 3: Red Hat Fuse 7: Red Hat OpenShift AI (RHOAI): Red Hat OpenShift Container Platform 4: Red Hat Openshift Data Foundation 4: Red Hat OpenShift GitOps: Red Hat Satellite 6: Red Hat Cryostat 4: Red Hat Multicluster Engine for Kubernetes: Red Hat Node HealthCheck Operator: Red Hat Advanced Cluster Management for Kubernetes 2: Red Hat AMQ Broker 7: Red Hat Ansible Automation Platform 2: Red Hat build of Apache Camel - HawtIO 4: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat JBoss Enterprise Application Platform Expansion Pack: Red Hat Process Automation 7: Red Hat Quay 3: Red Hat Single Sign-On 7:

Vulnerable Packages

The following package name and versions may be associated with CVE-2026-23950

Package Manager Vulnerable Package Versions Fixed In
npm tar <= 7.5.3 7.5.4

Exploit Probability

EPSS
0.15%
Percentile
4.76%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.