CVE-2021-25268
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedMultiple XSS vulnerabilities in Webadmin allow for privilege escalation from MySophos admin to SFOS admin in Sophos Firewall older than version 19.0 GA.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceCross-site scripting (XSS) vulnerabilities in the Webadmin interface of Sophos Firewall allow an authenticated MySophos administrator to escalate privileges to SFOS admin by injecting malicious scripts. This is a stored XSS issue enabling privilege escalation rather than session hijacking alone.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 19.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- High
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check the installed Sophos Firewall firmware versionAccess the Webadmin interface and navigate to Dashboard > System > System Information, or run 'version' command in the console to display the firmware versionAffected if The displayed firmware version is less than 19.0 (e.g., 18.x, 17.x, etc.)
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Verify Webadmin interface is enabledNavigate to Administration > Web Server in the Webadmin interface and confirm the Webadmin service statusAffected if Webadmin interface is enabled and accessible (this is the attack surface for the XSS)
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Confirm MySophos administrator accounts existNavigate to Authentication > Users > User Manager and check for any users with MySophos portal authentication typeAffected if At least one MySophos administrator account is configured in the system
The environment is affected if the Sophos Firewall firmware version is below 19.0 AND the Webadmin interface is accessible to MySophos administrators who could inject the malicious XSS payload.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped19.0
Upgrade Sophos Firewall to version 19.0 GA or later to remediate the vulnerability.
Sophos Firewall version 19.0 GA (or later stable release)
- Log into the Sophos Firewall management interface
- Navigate to the firmware update section under System > Firmware or Backup & Firmware
- Check the current firmware version to confirm it is below 19.0
- Download and apply Sophos Firewall version 19.0 GA or later from the Sophos support portal
- After upgrade, verify the Webadmin interface is functioning correctly and the XSS vulnerability is remediated
- Review admin user permissions to ensure no unauthorized privilege escalation occurred
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing12.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,432.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-25268 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-25268 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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