How severe is CVE-2021-43942?

CVE-2021-43942 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-43942 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 55% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43942?

CVE-2021-43942 primarily affects Atlassian Jira Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43942?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43942 published?

CVE-2021-43942 was published on 2022-01-04 and last updated on 2026-06-17.

CVE-2021-43942

CVE-2021-43942 is a medium-severity vulnerability in Atlassian Jira Server with a CVSS 3.x base score of 6.1. Its EPSS exploit-prediction score of 55% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 55% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Atlassian Jira Server
Published: 2022-01-04
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-43942?: 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.
How severe is CVE-2021-43942?: CVE-2021-43942 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-43942 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 55% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43942?: CVE-2021-43942 primarily affects Atlassian Jira Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43942?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43942 published?: CVE-2021-43942 was published on 2022-01-04 and last updated on 2026-06-17.

References

https://jira.atlassian.com/browse/JRASERVER-73068

Affected products (2)

cpe:2.3:a:atlassian:jira_server:*:*:*:*:*:*:*:*
cpe:2.3:a:atlassian:jira_server_and_data_center:*:*:*:*:*:*:*:*

More vulnerabilities in Atlassian Jira Server

CVE-2022-26136 — Critical (CVSS 9.8): A vulnerability in multiple Atlassian products allows a remote, unauthenticated attacker to bypass Servlet Filters used…
CVE-2022-0540 — Critical (CVSS 9.8): A vulnerability in Jira Seraph allows a remote, unauthenticated attacker to bypass authentication by sending a…
CVE-2019-11581 — Critical (CVSS 9.8): There was a server-side template injection vulnerability in Jira Server and Data Center, in the ContactAdministrators…
CVE-2025-22157 — High (CVSS 8.8): This High severity PrivEsc (Privilege Escalation) vulnerability was introduced in versions: 9.12.0, 10.3.0, 10.4.0,…
CVE-2024-21683 — High (CVSS 8.8): This High severity RCE (Remote Code Execution) vulnerability was introduced in version 5.2 of Confluence Data Center…
CVE-2022-26137 — High (CVSS 8.8): A vulnerability in multiple Atlassian products allows a remote, unauthenticated attacker to cause additional Servlet…

All CVEs affecting Atlassian Jira Server →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →