CVE-2026-77156: ast-cli: Path traversal in tar extraction on Linux/macOS allows writes outside the install directory

Severity: medium (CVSS 6.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-22 · updated 2026-10-23
Weakness: CWE-22

Description

Incomplete validation of extracted archive entry paths in ast-cli's tar extraction logic on Linux and macOS (used when installing the Vorpal ASCA real-time engine and the SCA Resolver) would allow a malicious tar archive containing absolute or traversal path entries to write files outside the install directory. Windows builds were not affected, as the Windows extractor performs this path validation. Exploitation required substituting the archive served at "download.checkmarx.com". An attacker able to compromise that server and replace the archive could write arbitrary, executable files to arbitrary filesystem paths via this path traversal. Extraction now validates that each entry's destination path resolves within the working directory and rejects absolute paths.

Affected products

Checkmarx github.com/checkmarx/ast-cli: before 2.3.51 — fixed in 2.3.51

How to fix

Upgrade to a fixed version: Checkmarx github.com/checkmarx/ast-cli 2.3.51. Check the vendor advisory for mitigations.

References

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