Sophos Firewall CVE-2022-1040 (authentication bypass in User Portal and Webadmin leading to remote code execution, CISA KEV): which versions are affected and how do I confirm the hotfix is installed?

Applies to: Sophos Firewall (SFOS) v18.5 MR3 and older without the CVE-2022-1040 hotfix; fixed in v18.5 MR4 and v19.0 GA

How it was checked: Compiled on 2026-10-31 from Sophos advisory sophos-sa-20220325-sfos-rce, NVD and the CISA KEV catalog (added 2022-03-31); not reproduced by Exuvia.

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sophos
firewall
sfos
auth-bypass
cve-2022-1040
kev
security

Fix

What it is: CVE-2022-1040, disclosed by Sophos on March 25, 2022, is an authentication bypass in the User Portal and Webadmin interfaces of Sophos Firewall (SFOS). An attacker who can reach those interfaces could run code on the firewall. Sophos reported it had been used against a small set of specific organizations, and CISA added it to the KEV catalog on March 31, 2022. Firewalls with admin or user portals on the WAN side remain targets. Am I affected: - Sophos Firewall v18.5 MR3 (18.5.3) and older without the hotfix. - Fixed in v19.0 GA and v18.5 MR4 (18.5.4); Sophos also pushed hotfixes to earlier branches (v17.0 MR10, v17.5 MR16/MR17, v18.0 MR5/MR6, v18.5 MR1-MR3). Firewalls with automatic hotfix installation on (the default) received it automatically; older unsupported versions must upgrade. - Exposure: User Portal or Webadmin reachable on the WAN interface. Fix: 1. Check the firmware version in Webadmin (or the console), confirm the hotfix for CVE-2022-1040 is listed as installed (Sophos documents how to verify hotfixes), and upgrade to a current supported SFOS release regardless. 2. Make sure automatic hotfix installation is enabled. 3. Take User Portal and Webadmin off the WAN (Sophos' workaround): use a VPN or Sophos Central / Fusion for remote access and management, and restrict device access settings on the WAN zone. 4. If the firewall ran an unpatched version with those interfaces exposed, check for unexpected admin accounts, configuration and rule changes, and follow Sophos guidance; rotate admin, VPN and directory credentials stored on it. Verify: the firewall shows a current firmware version, the hotfix is listed, and WAN-side access to User Portal and Webadmin is disabled. Sources: https://www.sophos.com/en-us/security-advisories/sophos-sa-20220325-sfos-rce https://nvd.nist.gov/vuln/detail/CVE-2022-1040 https://www.cisa.gov/known-exploited-vulnerabilities-catalog

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