CVE-2021-43942Network attack vector

Reflected XSS via unneutralized collector template input

Published Jan 4, 2022 · Updated Oct 8, 2024

Reflected XSS in Atlassian Jira Server and Data Center before 8.13.15 and 8.14.0 through 8.20.2 allows remote attackers to inject script. The /rest/collectors/1.0/template/custom endpoint places attacker-controlled template input into its HTML response without neutralizing markup or script. Exploitation requires a user to visit an attacker-controlled website, causing returned content to execute within the user's Jira browser context.

CVSS severity6.1
Medium
EPSS probability55.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Atlassian Jira Server and Data Center before 8.13.15 and 8.14.0 through 8.20.2 allows remote attackers to inject script. The /rest/collectors/1.0/template/custom endpoint places attacker-controlled template input into its HTML response without neutralizing markup or script. Exploitation requires a user to visit an attacker-controlled website, causing returned content to execute within the user's Jira browser context.

The record

CVE
CVE-2021-43942
Published
Jan 4, 2022
Updated
Oct 8, 2024
Vendor
Atlassian
Product
Jira Server
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Oct 8, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.14.0 <unspecified
  2. Affected versionversion=unspecified <8.13.15
  3. Affected versionversion=unspecified <8.20.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Atlassian · Jira Serverversion=8.14.0 <unspecified; version=unspecified <8.13.15; version=unspecified <8.20.3
Atlassian · Jira Data Centerversion=8.14.0 <unspecified; version=unspecified <8.13.15; version=unspecified <8.20.3

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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