Signed plug-in validation bypass

published 2026-11-04 5 d ago modified 2026-11-04 4 d ago also EUVD-2026-116803

cvss: 8.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits: 0; none known

The PFI plugin framework deploys executable assemblies (DLLs) from a signed plugin package into the local plugin repository and loads them via reflection, but the deployment routine processes archive entries that were never covered by the signature verification. An unauthenticated local attacker can replace an unsigned DLL outside the signed prefix in the archive passes verification and overwrites the legitimate signed assembly at the same destination path. The plugin loader then instantiates the attacker-supplied code without any additional integrity check resulting in a full compromise of the affected systems.

Patch / fix

fixed in 1

Phoenix Contact PLCnext Engineer 2026.6

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 4 d ago (2026-11-04)

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	3.1	8.4	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	8.6	CVSS:4.0/AV:L/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Phoenix Contact PLCnext Engineer

Classification

Weakness

CWE-494 Download of Code Without Integrity Check

References

certvde.com /en/advisories/VDE-2026-121/

Sources

CVE List CVE-2026-110022
NVD CVE-2026-110022

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary