keeva decompress up to 4.2.1 path traversal

Summaryinfo

A vulnerability identified as critical has been detected in keeva decompress up to 4.2.1. This vulnerability affects unknown code. The manipulation leads to path traversal. This vulnerability is referenced as CVE-2026-39245. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in keeva decompress up to 4.2.1. This issue affects some unknown functionality. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. 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. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

decompress before 4.2.2 contains an improper path containment check that enables directory traversal and arbitrary file write. The safeMakeDir function (index.js line 29) and the extraction path validation (index.js line 106) use String.indexOf() to verify the resolved path is within the output directory: realDestinationDir.indexOf(realOutputPath) !== 0. This check is flawed because it does not enforce a path separator boundary. For example, "/tmp/app_config".indexOf("/tmp/app") returns 0, incorrectly passing the check even though /tmp/app_config is outside /tmp/app. Combined with the unvalidated symlink creation in the same package, an attacker can write arbitrary files to directories adjacent to the extraction target. This is a bypass of the fix for CVE-2020-12265. The correct check requires appending a path separator: realParentPath.indexOf(realOutputPath + path.sep) !== 0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-39245 since 04/06/2026. The exploitation is known to be easy. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Upgrading to version 4.2.2 eliminates this vulnerability.

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Productinfo

Vendor

• keeva

Name

• decompress

Version

• 4.2.0
• 4.2.1

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

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