No exploitation reportedFix available

CVE-2021-43942

Q: Is CVE-2021-43942 actively exploited?

Active exploitation of CVE-2021-43942 has not been confirmed. Its EPSS score was 55.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-43942?

CVE-2021-43942 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

No exploitation reported by the sources we read.

Published2022-01-04
Fixed in8.20.3
WeaknessCWE-79

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to inject arbitrary HTML or JavaScript via a Reflected Cross-Site Scripting (XSS) vulnerability in the /rest/collectors/1.0/template/custom endpoint. To exploit this issue, the attacker must trick a user into visiting a malicious website. The affected versions are before version 8.13.15, and from version 8.14.0 before 8.20.3.

Timeline

dates in UTC

2022-01-0403:15CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-43942?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-43942?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Atlassian Jira

Branch	Affected	Fixed in	Source
8.x	≥ 8.14.0, < 8.20.3	8.20.3	NVD

Atlassian jira server and data center

Branch	Affected	Fixed in	Source
8.13	< 8.13.5	8.13.5	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Atlassian Jira to 8.20.3

Advisories and patches

jira.atlassian.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-10-08
OpenCVESSVC decisionnone—
NVDCVSS 3.16.1read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
NVDweakness (CWE)CWE-79read 2026-10-23
FIRST EPSSEPSS score55.4 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published: 2022-01-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-43942?

Is CVE-2021-43942 actively exploited?

Active exploitation of CVE-2021-43942 has not been confirmed. Its EPSS score was 55.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43942?

CVE-2021-43942 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

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