AUGUST 24, 2026
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Case File

CVE-2026-39245

MEDIUM · CVSS 6.2 EPSS 0.34% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-09 · Last synced 2026-08-08

CyberRota Analysis

AI-Generated

The vulnerability allows for directory traversal and arbitrary file writing due to an improper path containment check in the decompress package prior to version 4.2.2. This flaw can be exploited by attackers to write files outside the intended output directory, potentially compromising system integrity. Organizations using the affected versions of the decompress package should prioritize patching to mitigate the risk of unauthorized file access and manipulation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-39245
Severity
MEDIUM
CVSS
6.2
EPSS
0.34%

Original NVD Description

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.

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