Is CVE-2021-21087 actively exploited?

Yes. CVE-2021-21087 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-21087 be exploited remotely?

The attack vector of CVE-2021-21087 has not been classified yet.

What is the CVSS score of CVE-2021-21087?

CVE-2021-21087 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-21087

UNKNOWNCISA KEVIN THE WILD

CVE-2021-21087

Published: April 11, 2026

EPSS:84.20%probability of exploitation in 30 daysPercentile:99.3th

Official Description

Adobe Coldfusion versions 2016 (update 16 and earlier), 2018 (update 10 and earlier) and 2021.0.0.323925 are affected by an Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability. An attacker could abuse this vulnerability to execute arbitrary JavaScript code in context of the current user. Exploitation of this issue requires user interaction.

NVD Source

Technical Analysis

CVE-2021-21087 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-21087 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.