CVE-2021-21087
Medium PUBLISHEDColdFusion Improper neutralization of web input during page generation could lead to arbitrary JavaScript execution in the browser
Not yet in CISA KEV
Recommended Action
Treat as actively exploited. Assess exposure, apply compensating controls where patching is delayed, and monitor for abuse.
At a Glance
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.
- Published
- Apr 15, 2021
- First Seen
- Jul 26, 2025
- CVSS
- 5.4 Medium
- EPSS
- —
Recommended Actions
- Treat as actively exploited. Assess exposure, apply compensating controls where patching is delayed, and monitor for abuse.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
| Source | Added |
|---|---|
| The Shadowserver (via CIRCL) First | 2025-07-26 00:00 UTC |
Detection Context
Request patterns and scanner artifacts observed for this CVE. Operational detection logic guidance is coming soon.
Scanner Artifacts
Nuclei and Metasploit references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-21087.yaml | Apr 25, 2025 |
CVSS Scores
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Exploitation Status
Exploited in the wild
Recorded 2025-07-26 00:00:00 UTC · The Shadowserver (via CIRCL)
Proof of concept available
Recorded 2026-06-12 14:20:18 UTC · Nuclei Templates
Weaknesses (CWE)
-
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-21087.yaml | Apr 25, 2025 |
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
nuclei · Created Unknown
Timeline
-
Proof of Concept Exploit Available
-
Added to KEVIntel
-
Detected by Nuclei
-
CVE Published to Public
-
CVE ID Reserved
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v1/pro/kevs/CVE-2021-21087
{
"cve_id": "CVE-2021-21087",
"title": "ColdFusion Improper neutralization of web input during page generation could ...",
"affected_vendor": "Adobe",
"affected_product": "ColdFusion",
"confidence": "Medium",
"cvss_score": 5.4,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}