CVE-2026-1323: Cpsit/typo3 mailqueue The Mailqueue TYPO3 Extension Has Vulnerability

MODERATE
Advisory Identifier: GHSA-2pm6-9fhx-vvg3
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CVSS 8.8
CWE-502
Published
Advisory Summary

CVE-2026-1323 is a MODERATE (CVSS 8.8) the mailqueue typo3 extension has vulnerability (CWE-502: Deserialization of Untrusted Data) affecting Cpsit/typo3 mailqueue libraries in the Packagist ecosystem. The issue involves the mailqueue typo3 extension has insecure deserialization in `transportfailure` class. Remediation is available by upgrading affected packages to version 0.4.5, 0.5.2.

CVE-2026-1323 at a Glance

CVE Identifier CVE-2026-1323
GHSA Identifier GHSA-2pm6-9fhx-vvg3
Severity MODERATE
CVSS v3.1 Base Score 8.8
CWE Classification CWE-502: Deserialization of Untrusted Data
Affected Product Cpsit/typo3 mailqueue
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-1323

To remediate this vulnerability, upgrade all affected Cpsit/typo3 mailqueue dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

cpsit/typo3-mailqueue fixed: 0.4.5 
Upgrade cpsit/typo3-mailqueue to 0.4.5
cpsit/typo3-mailqueue fixed: 0.5.2 
Upgrade cpsit/typo3-mailqueue to 0.5.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for cpsit/typo3-mailqueue

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-1323, inspect your project dependencies for Cpsit/typo3 mailqueue:

inspect dependencies for cpsit/typo3-mailqueue

Analyze the terminal output to locate any version of Cpsit/typo3 mailqueue in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.4.5), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-502: Deserialization of Untrusted Data, where the product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. In Cpsit/typo3 mailqueue, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## 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']`.

CVE-2026-1323 Affected Cpsit/typo3 mailqueue Versions

2 component(s)
Fixed Versions:
0.4.50.5.2
Product / Package Ecosystem Affected Versions Fixed Version
cpsit/typo3-mailqueue
 Packagist
< 0.4.5
0.4.5
cpsit/typo3-mailqueue
 Packagist
≥ 0.5.0
< 0.5.2
0.5.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/CPS-IT/mailqueue/security/advisories/GHSA-2pm6-9fhx-vvg3
NVD — CVE-2026-1323 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-1323
Security Fix Commit FIX COMMIT
https://github.com/CPS-IT/mailqueue/commit/0f7a1376bbbd8c7658030d02e51c10a85b1dfdf7
Security Fix Commit FIX COMMIT
https://github.com/CPS-IT/mailqueue/commit/600c7dba99f8eea5f2505b848ee3dd4713440741
Cpsit/typo3 mailqueue Source Repository REPOSITORY
https://github.com/CPS-IT/mailqueue
Cpsit/typo3 mailqueue Security Information SECURITY
https://typo3.org/security/advisory/typo3-ext-sa-2026-005

Frequently Asked Questions

What is CVE-2026-1323?
CVE-2026-1323 is a security vulnerability in Cpsit/typo3 mailqueue involving The mailqueue TYPO3 extension has Insecure Deserialization in `TransportFailure` class under CWE-502: Deserialization of Untrusted Data.
Which Cpsit/typo3 mailqueue versions are affected?
Affected versions include releases prior to 0.4.5, 0.5.2 across affected packages: cpsit/typo3-mailqueue.
What version fixes CVE-2026-1323?
Upgrading to 0.4.5, 0.5.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is cpsit/typo3-mailqueue affected?
Yes, cpsit/typo3-mailqueue is affected in releases prior to 0.4.5, 0.5.2. Upgrade your dependency to 0.4.5, 0.5.2 or later.
What is the CVSS score of CVE-2026-1323?
CVE-2026-1323 has a CVSS v3.1 base score of 8.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-1323?
CVE-2026-1323 is classified under CWE-502: Deserialization of Untrusted Data (The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.).
How can I check Packagist dependencies for CVE-2026-1323?
Run the dependency tree command: 'inspect dependencies for cpsit/typo3-mailqueue'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2pm6-9fhx-vvg3",
  "modified" : "2026-04-27T16:45:24Z",
  "published" : "2026-03-18T16:17:08Z",
  "aliases" : [ "CVE-2026-1323" ],
  "summary" : "The mailqueue TYPO3 extension has Insecure Deserialization in `TransportFailure` class",
  "details" : "## Description\n\nThe 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']`.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "cpsit/typo3-mailqueue"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.4.5"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "cpsit/typo3-mailqueue"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.5.0"
      }, {
        "fixed" : "0.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/CPS-IT/mailqueue/security/advisories/GHSA-2pm6-9fhx-vvg3"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-1323"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/CPS-IT/mailqueue/commit/0f7a1376bbbd8c7658030d02e51c10a85b1dfdf7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/CPS-IT/mailqueue/commit/600c7dba99f8eea5f2505b848ee3dd4713440741"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/CPS-IT/mailqueue"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-ext-sa-2026-005"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-18T16:17:08Z",
    "nvd_published_at" : "2026-03-17T09:16:13Z"
  }
}