No exploitation reportedFix available

CVE-2021-20850

No exploitation reported by the sources we read.

Published2021-11-24
WeaknessCWE-78

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

PowerCMS XMLRPC API of PowerCMS 5.19 and earlier, PowerCMS 4.49 and earlier, PowerCMS 3.295 and earlier, and PowerCMS 2 Series (End-of-Life, EOL) allows a remote attacker to execute an arbitrary OS command via unspecified vectors.

Timeline

dates in UTC

2021-11-2416:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 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-2021-20850?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20850?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Alfasado powercms

Branch	Affected	Fixed in	Source
2.x	≥ 2.0, ≤ 2.058	no fix published	NVD
3.x	≥ 3.01, ≤ 3.295	no fix published	NVD
4.x	≥ 4.0, ≤ 4.49	no fix published	NVD
5.x	≥ 5.0, ≤ 5.19	no fix published	NVD

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

Fix

Advisories and patches

www.powercms.jpPatch · Vendor Advisory

Detection

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

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-78read 2026-10-23
FIRST EPSSEPSS score1.5 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-11-24
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-20850?

Is CVE-2021-20850 actively exploited?

Active exploitation of CVE-2021-20850 has not been confirmed. Its EPSS score was 1.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20850?

CVE-2021-20850 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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