How severe is CVE-2021-39123?

CVE-2021-39123 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-39123 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39123?

CVE-2021-39123 primarily affects Atlassian Data Center. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39123?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39123 published?

CVE-2021-39123 was published on 2021-09-14 and last updated on 2026-06-17.

CVE-2021-39123

CVE-2021-39123 is a high-severity vulnerability in Atlassian Data Center with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Atlassian Data Center
Published: 2021-09-14
Last modified: 2026-06-17

Description

Affected versions of Atlassian Jira Server and Data Center allow unauthenticated remote attackers to impact the application's availability via a Denial of Service (DoS) vulnerability in the /rest/gadget/1.0/createdVsResolved/generate endpoint. The affected versions are before version 8.16.0.

Frequently asked questions

What is CVE-2021-39123?: Affected versions of Atlassian Jira Server and Data Center allow unauthenticated remote attackers to impact the application's availability via a Denial of Service (DoS) vulnerability in the /rest/gadget/1.0/createdVsResolved/generate endpoint. The affected versions are before version 8.16.0.
How severe is CVE-2021-39123?: CVE-2021-39123 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-39123 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39123?: CVE-2021-39123 primarily affects Atlassian Data Center. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39123?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39123 published?: CVE-2021-39123 was published on 2021-09-14 and last updated on 2026-06-17.

References

https://jira.atlassian.com/browse/JRASERVER-72237

Affected products (2)

cpe:2.3:a:atlassian:data_center:*:*:*:*:*:*:*:*
cpe:2.3:a:atlassian:jira:*:*:*:*:*:*:*:*

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