Cyber Resilience

CVE-2026-8727

HighRCE

Published: 19 May 2026

Published
19 May 2026
Modified
19 May 2026
KEV Added
Patch
CVSS Score v4 7.1 CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/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
EPSS Score 0.0039 30.6th percentile
Risk Priority 14 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-8727 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Typo3 (inferred from references). Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 30.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

The Crawler extension passes the X-T3Crawler-Meta response header from crawled URLs directly to PHP's unserialize(). An attacker controlling a crawled endpoint can inject arbitrary serialized PHP objects, leading to Remote Code Execution on the TYPO3 server. Exploitation requires administrative privileges…

more

to configure a crawler-enabled page and trigger the crawl via a Scheduler task.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
Why these techniques?

Deserialization of untrusted data (CWE-502) in a web crawler component directly enables RCE; requires prior admin access so maps to initial/privileged app exploitation plus command execution.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

Affected Assets

Typo3
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-502

Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.

addresses: CWE-502

Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.

addresses: CWE-502

Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.

addresses: CWE-502

Validates or rejects untrusted serialized data before deserialization occurs.

addresses: CWE-502

Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.

addresses: CWE-502

Integrity verification of serialized information can detect tampering before deserialization occurs.

addresses: CWE-502

Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.

References