CVE-2026-80427: Nfriedly Bestzip

High severity, CVSS 8.4. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Nfriedly Bestzip: before 2.2.6 (fixed in 2.2.6); from 3.0.0, before 3.0.2 (fixed in 3.0.2)

Published 2026-08-26. Last modified 2026-09-24.