FirewallApplication · Sophos

CVE-2023-5552

HIGH · 7.5 CVSS v3.1 Published 2023-10-18
Fix available
A fix is available. Upgrade to after 19.5.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A password disclosure vulnerability in the Secure PDF eXchange (SPX) feature allows attackers with full email access to decrypt PDFs in Sophos Firewall version 19.5 MR3 (19.5.3) and older, if the password type is set to “Specified by sender”.

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 confidence

A password disclosure vulnerability in Sophos Firewall's Secure PDF eXchange (SPX) feature allows attackers with full email access to decrypt password-protected PDFs when the password type is set to 'Specified by sender'. The vulnerability affects versions 19.5 MR3 (19.5.3) and older.

MitigationUpgrade Sophos Firewall to a version newer than 19.5 MR3, or change the SPX password type setting from 'Specified by sender' to an alternative configuration if available.

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
FirewallApplication
Affected:<= 19.5.3

CVSS 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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify Sophos Firewall version
    Access the Sophos Firewall admin console and navigate to System > Administration > System > Firmware, or run 'version' command via CLI to check the installed firmware version.
    Affected if The installed version is 19.5 MR3 (19.5.3) or any version older than 19.5.3.
  2. Confirm SPX feature is enabled
    Navigate to Email > SPX in the Sophos Firewall admin console, or check the configuration via CLI with 'spx' or 'show spx' commands.
    Affected if The Secure PDF eXchange (SPX) feature is enabled and configured.
  3. Check SPX password type setting
    In the admin console, go to Email > SPX > Password Settings, or query the configuration to identify the current password type configuration.
    Affected if The password type is set to 'Specified by sender' (as opposed to other available password options).

A user is affected if their Sophos Firewall runs version 19.5.3 or older AND has SPX enabled with the password type configured as 'Specified by sender'.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to a release after 19.5.3
Interim mitigation

Upgrade Sophos Firewall to a version newer than 19.5 MR3, or change the SPX password type setting from 'Specified by sender' to an alternative configuration if available.

Recommended fix Moderate confidence

Sophos Firewall v19.5 MR4 or latest stable release

  1. 1. Log into Sophos Firewall Admin Console
  2. 2. Navigate to the Secure PDF eXchange (SPX) settings under Mail settings or Email protection
  3. 3. Change the password type from 'Specified by sender' to either 'User password' or 'Generated by system' to mitigate the vulnerability immediately
  4. 4. Check Sophos support for the latest fixed version (v19.5 MR4 or later)
  5. 5. Plan and schedule a firmware upgrade to the latest Sophos Firewall release
  6. 6. After upgrade, verify SPX functionality and ensure password protection is working correctly
  7. 7. Review audit logs for any suspicious PDF access attempts
Caveat Review release notes for any configuration or feature changes between 19.5.3 and the target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Firewall Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-5552 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data