No exploitation reportedFix available

CVE-2020-12517

Q: Is CVE-2020-12517 actively exploited?

Active exploitation of CVE-2020-12517 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-12517?

CVE-2020-12517 has a CVSS v3 base score of 9 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2020-12-17
Fixed in2021.0
WeaknessCWE-79

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

On Phoenix Contact PLCnext Control Devices versions before 2021.0 LTS an authenticated low privileged user could embed malicious Javascript code to gain admin rights when the admin user visits the vulnerable website (local privilege escalation).

Timeline

dates in UTC

2020-12-1723:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-12517?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-12517?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Phoenixcontact plcnext firmwareversion to verify

Branch	Affected	Fixed in	Source
2021.0	< 2021.0	2021.0	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Phoenixcontact plcnext firmware to 2021.0

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.18.8read 2026-10-23
NVDCVSS 3.19read 2026-10-23
NVDCVSS 2.06read 2026-10-23
CNAweakness (CWE)CWE-79read 2026-10-23
NVDweakness (CWE)CWE-79read 2026-10-23
FIRST EPSSEPSS score1.1 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Published: 2020-12-17
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-12517?

Is CVE-2020-12517 actively exploited?

Active exploitation of CVE-2020-12517 has not been confirmed. Its EPSS score was 1.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-12517?

CVE-2020-12517 has a CVSS v3 base score of 9 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

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