CVE-2026-45491

A flaw was found in .NET's System.Formats.Tar library. When extracting a specially crafted TAR archive containing symbolic links, the TarFile.ExtractToDirectory() method may incorrectly follow those links and write files outside the intended extraction directory. An attacker could exploit this issue to create or overwrite files in locations accessible to the extracting process, potentially leading to unauthorized file modification.

This vulnerability affects .NET's TAR archive extraction functionality. Red Hat Product Security has assessed this issue as a Moderate severity vulnerability.

The flaw occurs in System.Formats.Tar when processing TAR archives containing symbolic links. During extraction, the TarFile.ExtractToDirectory() method may incorrectly follow symlink paths and write files outside the intended extraction directory.

Successful exploitation requires a vulnerable application to process a specially crafted TAR archive. An attacker could use this behavior to create or overwrite files in locations accessible to the extracting process, potentially affecting system or application integrity.

The vulnerability is a symlink path traversal issue that results in unauthorized file modification outside the designated extraction directory. The primary security impact is integrity compromise through arbitrary file writes.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Red Hat is not aware of a practical temporary workaround that fully mitigates this issue or meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the relevant security updates when they become available.