dbcve.org
MailApplication · Nextcloud

CVE-2022-31132

CRITICAL · 9.8 CVSS v3.1 Published 2022-08-04
Fix available
A fix is available. Upgrade to 1.12.8 / 1.13.6 or later.
See remediation →
100/100
Remediation priority · Urgent
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
Nextcloud Mail is an email application for the nextcloud personal cloud product. Affected versions shipped with a CSS minifier on the path `./vendor/cerdic/css-tidy/css_optimiser.php`. Access to the minifier is unrestricted and access may lead to Server-Side Request Forgery (SSRF). It is recommendet to upgrade to Mail 1.12.7 or Mail 1.13.6. Users unable to upgrade may manually delete the file located at `./vendor/cerdic/css-tidy/css_optimiser.php`

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 · high confidence

Nextcloud Mail shipped with an unrestricted CSS minifier file at ./vendor/cerdic/css-tidy/css_optimiser.php. This file can be accessed remotely without authentication and can be induced to make arbitrary HTTP requests to attacker-controlled servers, leading to Server-Side Request Forgery (SSRF).

MitigationUpgrade to Mail 1.12.7 or 1.13.6, or manually delete the vulnerable css_optimiser.php file from the vendor directory.

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
MailApplication
Affected:< 1.12.8>= 1.13.0, < 1.13.6

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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checks

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

  1. Check Nextcloud Mail version
    Log into Nextcloud as admin, navigate to Apps section, find Mail app, and note the version number. Alternatively, check the version in the appinfo/info.xml file within the mail app directory.
    Affected if Version is below 1.12.8, or between 1.13.0 and 1.13.5 inclusive
  2. Verify vulnerable file exists
    Locate the file at ./vendor/cerdic/css-tidy/css_optimiser.php within the Nextcloud Mail app directory. Use file manager or command line: find /path/to/nextcloud/apps/mail -name 'css_optimiser.php' -path '*/vendor/cerdic/css-tidy/*'
    Affected if The file exists in the vendor directory of the Mail app
  3. Confirm remote file accessibility
    Attempt to access the URL directly via web browser or curl: https://your-nextcloud-instance/apps/mail/vendor/cerdic/css-tidy/css_optimiser.php. No authentication should be required for the request.
    Affected if The file is accessible over the web without any authentication required

You are affected if your Nextcloud Mail version is in the affected range AND the vulnerable css_optimiser.php file exists and is accessible without authentication.

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 1.12.8 / 1.13.6 or later
Fixed in 1.12.81.13.6
Interim mitigation

Upgrade to Mail 1.12.7 or 1.13.6, or manually delete the vulnerable css_optimiser.php file from the vendor directory.

Recommended fix High confidence

Nextcloud Mail 1.12.8 or 1.13.6

  1. 1. Back up your Nextcloud instance and database before proceeding
  2. 2. Update Nextcloud Mail to version 1.12.8 or higher from the Nextcloud App Store or via composer
  3. 3. Alternatively, update to version 1.13.6 or higher
  4. 4. After upgrade, verify the file ./vendor/cerdic/css-tidy/css_optimiser.php has been removed or is no longer accessible
  5. 5. Test that email functionality works correctly after the upgrade
Caveat Standard minor version upgrade; review Nextcloud compatibility matrix for your Nextcloud core version

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

Fix this in Mail Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-31132 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2022-31132 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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