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CVE-2026-1323 — typo3-mailqueue

Fix: CPS-IT/mailqueue@0f7a137

CVE-2026-1323 is a Deserialization of Untrusted Data vulnerability in cpsit/typo3-mailqueue. A fix is available for cpsit/typo3-mailqueue — see the affected versions and patch details below.

Insecure Deserialization in extension "Mailqueue" (mailqueue)

Also known asGHSA-2pm6-9fhx-vvg3
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-1323.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk+0.00%
Lower risk than most CVEs14th percentile — riskier than 14% of all scored CVEsHighest risk
0.00%0.24%0.49%0.73%0.1%0.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected
🐘cpsit/typo3-mailqueue🐘cpsit/typo3-mailqueue

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Description

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'].

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistcpsit/typo3-mailqueueall versions0.4.5composer require cpsit/typo3-mailqueue:^0.4.5
🐘Packagistcpsit/typo3-mailqueue≥ 0.5.0&&< 0.5.20.5.2composer require cpsit/typo3-mailqueue:^0.5.2

Affected Products

1 product · 2 configurations
Application
mailqueuecps-it
≥ 0.5.0 && < 0.5.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cpsit/typo3-mailqueue, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update cpsit/typo3-mailqueue to 0.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-1323 is resolved across your whole dependency graph.

  3. Workarounds

    Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

## Description 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']`.
O3 Security · Impact-Aware SCA

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CVE-2026-1323: typo3-mailqueue — Fixed in 0.4.5