CVE-2026-80427: bestzip Vulnerability (CVSS 8.4)

Description

bestzip builds the argument list for the system zip utility without separating options from operands. The destination archive path and the caller-supplied source paths are passed to the child process with no -- delimiter between them, so any source entry beginning with a hyphen is interpreted by zip as an option rather than a file name. zip accepts -T to test the finished archive and -TT to name the command used to perform that test, so a source list containing those two entries and a command string causes zip to run that command through a shell once the archive has been written. An application that passes a file name or path it received from an untrusted source into the bestzip API therefore executes a command of the supplier's choosing. Versions 2.2.6 and 3.0.2 add the delimiter.

Metrics

CVSS 3.1

8.4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

8.6/10

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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

EPSS Probability

0.22%

11.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-88

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
nfriedly	bestzip	< 2.2.6; >= 3.0.0, < 3.0.2

References

Timeline

Published: Aug 26, 2026
Last Modified: Sep 24, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-80427?

bestzip builds the argument list for the system zip utility without separating options from operands. The destination archive path and the caller-supplied source paths are passed to the child process with no -- delimiter between them, so any source entry beginning with a hyphen is interpreted by zip as an option rather than a file name. zip accepts -T to test the finished archive and -TT to name the command used to perform that test, so a source list containing those two entries and a command string causes zip to run that command through a shell once the archive has been written. An application that passes a file name or path it received from an untrusted source into the bestzip API therefore executes a command of the supplier's choosing. Versions 2.2.6 and 3.0.2 add the delimiter.

How severe is CVE-2026-80427?

CVE-2026-80427 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.

How do I fix CVE-2026-80427?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →