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HIGH

CVE-2026-23950

CVSS v3

8.8

HIGH

EPSS Score

0.3 %

exploit probability, as of 2026-10-17

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • tarnpmall versions · fixed in 7.5.4
  • sgx-pccsAlmaLinux:10all versions · fixed in 2.26-7.el10and 6 other packages
  • sgx-pccsAlmaLinux:9all versions · fixed in 2.26-7.el9and 6 other packages

Vendor advisories

  • CVE-2026-23950 Red Hat Product Security40 products fixed · 28 known affected

    node-tar: tar: node-tar: Arbitrary file overwrite via Unicode path collision race condition

    openshift-sandboxed-containers/osc-pccs as a component of Confidential Compute Attestation · openshift-logging/kibana6-rhel8 as a component of Logging Subsystem for Red Hat OpenShift · rhmtc/openshift-migration-ui-rhel8 as a component of Migration Toolkit for Containers

  • RHSA-2026:18868 Red Hat Product Security17 products fixed

    Red Hat Security Advisory: linux-sgx security update

  • RHSA-2026:18480 Red Hat Product Security17 products fixed

    Red Hat Security Advisory: linux-sgx security update

  • RHSA-2026:6192 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.27.0 Release.

  • RHSA-2026:2926 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: RHTAS 1.2.2 - Red Hat Trusted Artifact Signer Release

  • RHSA-2026:2144 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: RHTAS 1.3.2 - Red Hat Trusted Artifact Signer Release

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
Published
2026-01-20
Last Modified
2026-02-18

Frequently asked questions

What is CVE-2026-23950?

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.

Is CVE-2026-23950 actively exploited?

Active exploitation of CVE-2026-23950 has not been confirmed. Its EPSS score was 0.3% on 2026-10-17, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-23950?

CVE-2026-23950 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L.

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