CVE-2026-1323 Insecure Deserialization in extension "Mailqueue" (mailqueue)
An attacker with write access to the mail spool directory can execute arbitrary code via insecure deserialization in the TYPO3 Mailqueue extension.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-1323?
CVE-2026-1323 is a medium-severity unsafe deserialization vulnerability in TYPO3 Extension "Mailqueue", published on 17 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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'].
Weakness: CWE-502
Which versions are affected by CVE-2026-1323?
4 open source packages ship an affected version, including cpsit/typo3-mailqueue. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
cpsit/typo3-mailqueue Packagist | All versions | 0.4.5 |
cpsit/typo3-mailqueue Packagist | All versions | 0.4.5 |
cpsit/typo3-mailqueue Packagist | From 0.5.0 | 0.5.2 |
cpsit/typo3-mailqueue Packagist | From 0.5.0 | 0.5.2 |
Products include Cps-It Mailqueue.
How do I fix CVE-2026-1323?
Upgrade cpsit/typo3-mailqueue to a fixed version for your release line: 0.4.5 or 0.5.2.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-1323 being exploited?
There is no known exploitation of CVE-2026-1323 in the wild and no public exploit code.
Sources
Also known as GHSA-2pm6-9fhx-vvg3.