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UK Cyber Defence
VulnerabilityDeferred

CVE-2026-77138

The extension fails to safely process untrusted client input of an attacker-controlled cookie directly to PHP's unserialize().

CRITICAL 9.3EPSS 0.72%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.72%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The extension fails to safely process untrusted client input of an attacker-controlled cookie directly to PHP's unserialize(). A remote, unauthenticated attacker can supply a crafted serialized payload to trigger PHP Object Injection, leading to Remote Code Execution on the TYPO3 server.

CVSS 4.0
9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.72% probability · 53th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-502
Source
f4fb688c-4412-4426-b4b8-421ecf27b14a
EPSS trend
0%3%5%26 October 2026: 0.72%26 October 202626 October 2026

EPSS 0.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.