CVE-2021-21087 | ColdFusion Improper neutralization of web input during page generation could lead to arbitrary JavaScript execution in the browser

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: 2021-04-15 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21087 is rated Moderate Risk (60.6/100): CVSS Medium severity, with high exploitation likelihood (EPSS 84.20%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +4.27% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-21087

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-25 79.93% 84.20% +4.27%
2 2026-03-18 84.20% 79.93% -4.27%
3 2026-03-04 — 84.20% —

Full EPSS history (62 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21087

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
5.4 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2021-21087

Affected software / configurations for CVE-2021-21087

Vendor Product Version Raw CPE
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:-:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update1:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update10:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update11:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update12:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update13:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update14:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update15:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update16:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update2:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update3:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update4:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update5:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update6:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update7:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update8:*:*:*:*:*:*
adobe coldfusion 2016 cpe:2.3:a:adobe:coldfusion:2016:update9:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:-:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update1:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update10:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update2:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update3:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update4:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update5:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update6:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update7:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update8:*:*:*:*:*:*
adobe coldfusion 2018 cpe:2.3:a:adobe:coldfusion:2018:update9:*:*:*:*:*:*
adobe coldfusion 2021.0.0.323925 cpe:2.3:a:adobe:coldfusion:2021.0.0.323925:*:*:*:*:*:*:*

References for CVE-2021-21087

cvelogic Threat Intelligence