# CVE-2026-110021: Missing GSDX SignatureValue verification

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

PLCnext Engineer checks GSDX manifest reference digests but does not cryptographically verify the XML `SignatureValue` over canonicalized `SignedInfo`. An unauthenticated local attacker can modify signed GSDML content, update its manifest digest, retain the public certificate data, and leave an invalid nonempty `SignatureValue`. PLCnext Engineer prior to 2026.6 reports the package as `Valid` and selects the modified device description for import under the default policy.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Phoenix Contact / PLCnext Engineer: ≥ 0.0; < 2026.6 (affected, semver). Source: CNA: CERTVDE

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N; source: CNA: CERTVDE

- CVSS 3.1: 6.2 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N; source: CNA: CERTVDE

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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; source: NVD: info@cert.vde.com

- CVSS 3.1: 6.2 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N; source: NVD: info@cert.vde.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-347

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://www.certvde.com/en/advisories/VDE-2026-121/ (CNA: CERTVDE)

- https://www.certvde.com/en/advisories/VDE-2026-121/ (info@cert.vde.com)

## Provenance

- CNA: CERTVDE: https://www.cve.org/CVERecord?id=CVE-2026-110021; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110021; retrieved 2026-11-04; source updated 2026-11-04

Revision: 7476c704fc9a750011a1f44b702f17ca79ae8c46c12f21a40ba1fa60ab132eea

Canonical: https://y2.dev/cve/CVE-2026-110021

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