CVE-2026-23950

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.

CVSS Metrics

• v3.1•HIGH•Score: 8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
• v3.1•MEDIUM•Score: 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Trends

Current EPSS score: 0.26%• Percentile: 18%

Techniques & Countermeasures

• CWE-176•Improper Handling of Unicode Encoding

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

• CWE-352•Cross-Site Request Forgery (CSRF)

  The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

• CWE-367•Time-of-check Time-of-use (TOCTOU) Race Condition

  The product 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.

Affected Systems

• chainguard•actions-runner

  < 2.331.0-r1

• chainguard•code-server

  < 4.106.3-r4

• chainguard•drupal-11.3

  < 11.3.13-r3

• chainguard•gitlab-rails-ce-18.1

  < 18.1.6-r31

• chainguard•gitlab-rails-ce-18.10

  all

• chainguard•gitlab-rails-ce-18.11

  < 18.11.6-r12

• chainguard•gitlab-rails-ce-18.5

  all

• chainguard•gitlab-rails-ce-18.6

  all

• chainguard•gitlab-rails-ce-18.7

  all

• chainguard•gitlab-rails-ce-18.8

  all

• chainguard•gitlab-rails-ce-18.9

  all

• chainguard•gitlab-rails-ce-19.0

  < 19.0.4-r10 | < 19.0.3-r1

• chainguard•gitlab-rails-ce-19.1

  < 19.1.2-r8

• chainguard•gitlab-rails-ce-19.2

  < 19.2.2-r2

• chainguard•gitlab-rails-ce-fips-18.1

  < 18.1.6-r15 | < 18.1.6-r61

• chainguard•gitlab-rails-ce-fips-18.10

  all

• chainguard•gitlab-rails-ce-fips-18.11

  all

• chainguard•gitlab-rails-ce-fips-18.5

  all

• chainguard•gitlab-rails-ce-fips-18.6

  all

• chainguard•gitlab-rails-ce-fips-18.7

  all

• chainguard•gitlab-rails-ce-fips-18.8

  all

• chainguard•gitlab-rails-ce-fips-18.9

  all

• chainguard•gitlab-rails-ce-fips-19.0

  < 19.0.4-r7

• chainguard•gitlab-rails-ce-fips-19.1

  < 19.1.1-r1 | < 19.1.2-r9

• chainguard•gitlab-rails-ce-fips-19.2

  < 19.2.1-r4

• chainguard•graalvm-23-ce-nodejs

  all

• chainguard•graalvm-24-ce-nodejs

  all

• chainguard•graalvm-25-ce-nodejs

  < 25.0.2-r1

• chainguard•jupyter-base-notebook

  all

• chainguard•katib-earlystopping

  < 0.19.0-r31

• chainguard•katib-suggestion-goptuna-compat

  < 0.19.0-r40

• chainguard•katib-suggestion-hyperband

  < 0.19.0-r31

• chainguard•katib-suggestion-hyperopt

  < 0.19.0-r31 | < 0.19.0-r40

• chainguard•katib-suggestion-nas-darts

  < 0.19.0-r31

• chainguard•katib-suggestion-nas-enas

  < 0.19.0-r31

• chainguard•katib-suggestion-optuna-enas

  < 0.19.0-r31

• chainguard•katib-suggestion-pbt-enas

  < 0.19.0-r31

• chainguard•katib-suggestion-skopt-enas

  < 0.19.0-r31

• chainguard•katib-tfevent-metricscollector

  < 0.19.0-r31

• chainguard•kibana-7

  all

• chainguard•kibana-8.17

  < 8.17.10-r8

• chainguard•kibana-8.17-iamguarded

  < 8.17.10-r8

• chainguard•kibana-8.18

  < 8.18.8-r8

• chainguard•kibana-8.18-iamguarded

  < 8.18.8-r8

• chainguard•kibana-8.19

  < 8.19.10-r2

• chainguard•kibana-8.19-iamguarded

  < 8.19.10-r2

• chainguard•kibana-9.0

  < 9.0.8-r8

• chainguard•kibana-9.0-bitnami

  < 9.0.8-r8

• chainguard•kibana-9.0-iamguarded

  < 9.0.8-r8

• chainguard•kibana-9.1

  < 9.1.10-r3

Showing first 50 affected entries in server-rendered view.

References (16)

• https://github.com/isaacs/node-tar/security/advisories/GHSA-r6q2-hw4h-h46w
• https://github.com/isaacs/node-tar/commit/3b1abfae650056edfabcbe0a0df5954d390521e6
• https://nvd.nist.gov/vuln/detail/CVE-2026-23950
• https://github.com/isaacs/node-tar
• https://access.redhat.com/security/cve/CVE-2026-23950
• https://bugzilla.redhat.com/show_bug.cgi?id=2431036
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23950.json
• https://access.redhat.com/errata/RHSA-2026:18480
• https://access.redhat.com/errata/RHSA-2026:18868
• https://access.redhat.com/errata/RHSA-2026:6192
• https://access.redhat.com/errata/RHSA-2026:2926
• https://access.redhat.com/errata/RHSA-2026:2144
• https://ubuntu.com/security/CVE-2026-23950
• https://www.cve.org/CVERecord?id=CVE-2026-23950
• https://security-tracker.debian.org/tracker/CVE-2026-23950
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23950.json