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MailqueueTYPO3 extension · Cps It

CVE-2026-1323

HIGH · 8.8 CVSS v3.1 Published 2026-03-17
Fix available
A fix is available. Upgrade to 0.4.5 / 0.5.2 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
The extension fails to properly define allowed classes used when deserializing transport failure metadata. An attacker may exploit this to execute untrusted serialized code. Note that an active exploit requires write access to the directory configured at $GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport_spool_filepath'].

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

This is an insecure deserialization vulnerability in a TYPO3 extension where PHP's unserialize() is used without restricting allowed classes. An attacker with write access to the mail transport spool directory can inject malicious serialized payloads to achieve remote code execution.

MitigationDefine an explicit whitelist of allowed classes using the unserialize() second parameter (allowed_classes option) to prevent deserialization of untrusted objects. Alternatively, replace PHP serialization with safer formats like JSON.

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
MailqueueTYPO3 extension
Affected:< 0.4.5>= 0.5.0, < 0.5.2

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

CVSS:3.1/AV:N/AC:L/PR:L/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. Identify if Cps It Mailqueue extension is installed
    Check the TYPO3 extension manager or list installed extensions. Look for 'cps_it_mailqueue' or 'Cps It Mailqueue' in the extension list.
    Affected if The extension is not installed - not affected. If installed, proceed to version check.
  2. Determine installed version of Cps It Mailqueue
    In TYPO3 backend, go to Extension Manager > Cps It Mailqueue > check version field. Alternatively, inspect the extension's ext_emconf.php file in typo3conf/ext/cps_it_mailqueue/
    Affected if Version is < 0.4.5 OR >= 0.5.0 AND < 0.5.2 - potentially affected. Version 0.4.5 or >= 0.5.2 - not affected.
  3. Check if mail spool transport is configured
    Inspect $GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport'] in TYPO3 configuration (LocalConfiguration.php or AdditionalConfiguration.php). Also check $GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport_spool_filepath'].
    Affected if Mail transport is NOT set to 'spool' - not affected. If set to 'spool', proceed to spool directory check.
  4. Verify write access to mail spool directory
    Check filesystem permissions on the directory specified in $GLOBALS['TYPO3_CONF_VARS']['MAIL']['transport_spool_filepath']. Use ls -la command or file permission inspection.
    Affected if The spool directory is world-writable or writable by untrusted users - vulnerable to injection. If only writable by trusted users, the exploit risk is reduced but the code flaw still exists.

User is affected if Cps It Mailqueue extension versions < 0.4.5 or >= 0.5.0 and < 0.5.2 are installed AND the mail spool transport is enabled with a writable spool directory.

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 0.4.5 / 0.5.2 or later
Fixed in 0.4.50.5.2
Interim mitigation

Define an explicit whitelist of allowed classes using the unserialize() second parameter (allowed_classes option) to prevent deserialization of untrusted objects. Alternatively, replace PHP serialization with safer formats like JSON.

Recommended fix Moderate confidence

Upgrade to mailqueue version 0.5.2 or later (or 0.4.5 if staying on the 0.4.x branch)

  1. 1. Log in to the TYPO3 backend as an administrator with extension management permissions
  2. 2. Navigate to the Extension Manager (Admin Tools > Extensions)
  3. 3. Locate the 'mailqueue' extension in the list of installed extensions
  4. 4. Check the currently installed version - if it is below 0.4.5, or between 0.5.0 and 0.5.1, an update is required
  5. 5. Click the update button next to the mailqueue extension to fetch and install the latest version from the TYPO3 Extension Repository
  6. 6. Alternatively, if using Composer, run: composer require typo3/cms-mailqueue:^0.5.2 (or ^0.4.5 for older installations)
  7. 7. Clear all caches after the update via Admin Tools > Cache > Flush all caches
  8. 8. Verify the new version is reflected in the Extension Manager

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

Fix this in Mailqueue Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

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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-2026-1323 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