What it is
CVE-2021-21087 is a vulnerability affecting Adobe ColdFusion. 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...
Vulnerability report
Exploited in the wild
High confidence
Not in CISA KEV
CVE-2021-21087
ColdFusion Cross-Site Scripting
Adobe / ColdFusion · unspecified to <= 2016.16
- Severity
- CVSS 5.4 · Medium
- Confidence
- High
- Exploit status
- Exploited in the wild
- EPSS
- 37.1%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEVIntel tracks this CVE as a known exploited vulnerability. Confidence is high.
Who is affected?
Adobe / ColdFusion unspecified to <= 2016.16.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
ColdFusion Cross-Site Scripting
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.
Vendor
Product
Affected
Status
Adobe
ColdFusion
Through 2016.16
Affected
Adobe
ColdFusion
Through 2018.10
Affected
Adobe
ColdFusion
Through 2021.0.0.323925
Affected
Adobe
ColdFusion
Through None
Affected
- Published
- 15 Apr 2021
- Exploitation Reported
- 26 Jul 2025
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
Tags
nuclei_scanner
CVE References
- helpx.adobe.com/security/products/coldfusion/apsb21-16.html helpx.adobe.com · CVE Record https://helpx.adobe.com/security/products/coldfusion/apsb21-16.html
Exploitation evidence
Why KEVIntel marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
The Shadowserver
Independent exploitation attestation added to the KEVIntel record.
Proof of concept available
Nuclei Templates
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| The Shadowserver First | 2025-07-26 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
Nuclei template detected 25 Apr 2025.
View Nuclei template (opens in new tab)Virtual patch status
No KEVIntel virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-21087.yaml | 25 Apr 2025 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.0
5.4
Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS
37.1%
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
Adobe ColdFusion - Cross-Site Scripting
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
Public PoC available
Public proof-of-concept code published
-
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
Nuclei template available
Scanner coverage available
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2021-21087
Free JSON includes basic KEV fields{
"cve_id": "CVE-2021-21087",
"confidence": "High",
"cvss_score": 5.4,
"epss_score": 0.37095,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}