emp3r0r is a stealth-focused C2 designed by Linux users for Linux environments. Prior to 3.21.1, untrusted agent metadata (Transport, Hostname) is accepted during check-in and later interpolated into tmux shell command strings executed via /bin/sh -c. This enables command injection and remote code execution on the operator host. This vulnerability is fixed in 3.21.1.
https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-h5p4-4xp4-vjpp
https://github.com/jm33-m0/emp3r0r/releases/tag/v3.21.1
https://github.com/jm33-m0/emp3r0r/commit/0cd64e4a26e7839a9a54bca3d756a665fcb7fda0
Published: 2026-02-12
Updated: 2026-02-13
Base Score: 9
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:C
Severity: High
Base Score: 8.8
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 9.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Severity: Critical
EPSS: 0.00567