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Fencer Vulns
medium 6.4

CVE-2026-77157 json

ast-cli: Auto-update downloads are not verified against a checksum before execution

published 2026-10-22 17 d ago modified 2026-11-02 6 d ago also EUVD-2026-108271

cvss
6.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

ast-cli downloads two helper binaries, the Vorpal ASCA real-time engine and the SCA Resolver, from "download.checkmarx.com" as part of its auto-update flow, triggered by the Checkmarx’s "VSCode/JetBrains" extensions and by cx scan "sca-realtime".

Prior to the fix, the downloaded archive was not verified against a checksum before extraction and execution. An attacker able to substitute the served archive could deliver an arbitrary binary that ast-cli would extract and execute the contents of the archive, since no integrity check was performed on the download.

Successful exploitation requires compromising "download.checkmarx.com" and replacing the served archive with one containing an attacker-controlled binary. If the served archive had been replaced that way, any developer machine or CI pipeline invoking ASCA (via Checkmarx's VSCode/JetBrains extensions) or cx scan "sca-realtime" on an affected version would have extracted and executed that binary in place of the intended download.

The download is now verified against a published SHA-256 checksum before extraction.

Patch / fix

  • Checkmarx github.com/checkmarx/ast-cli 2.3.60

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 d ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.4 CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • Checkmarx github.com/checkmarx/ast-cli

Classification

Weakness
  • CWE-353 Missing Support for Integrity Check

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.