Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4DescriptionCVE.org
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'].
AnalysisAI
Unsafe deserialization in TYPO3's mail transport extension permits arbitrary code execution when an attacker with write access to the configured spool directory supplies malicious serialized objects during transport failure handling. The vulnerability stems from inadequate class whitelisting during deserialization and requires local filesystem access to exploit. No patch is currently available.
Technical ContextAI
Insecure deserialization occurs when untrusted data is used to reconstruct objects, allowing attackers to manipulate serialized data to execute arbitrary code. This vulnerability is classified as Deserialization of Untrusted Data (CWE-502).
RemediationAI
Avoid deserializing untrusted data. Use safe serialization formats (JSON instead of native serialization). Implement integrity checks on serialized data.
Same weakness CWE-502 – Deserialization of Untrusted Data
View allSame technique Deserialization
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-12548
GHSA-2pm6-9fhx-vvg3