How severe is CVE-2021-39121?

CVE-2021-39121 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-39121 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39121?

CVE-2021-39121 primarily affects Atlassian Data Center. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39121?

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

When was CVE-2021-39121 published?

CVE-2021-39121 was published on 2021-09-08 and last updated on 2026-06-17.

CVE-2021-39121

CVE-2021-39121 is a medium-severity vulnerability in Atlassian Data Center with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Atlassian Data Center
Published: 2021-09-08
Last modified: 2026-06-17

Description

Affected versions of Atlassian Jira Server and Data Center allow authenticated remote attackers to enumerate the keys of private Jira projects via an Information Disclosure vulnerability in the /rest/api/latest/projectvalidate/key endpoint. The affected versions are before version 8.5.18, from version 8.6.0 before 8.13.10, and from version 8.14.0 before 8.18.2.

Frequently asked questions

What is CVE-2021-39121?: Affected versions of Atlassian Jira Server and Data Center allow authenticated remote attackers to enumerate the keys of private Jira projects via an Information Disclosure vulnerability in the /rest/api/latest/projectvalidate/key endpoint. The affected versions are before version 8.5.18, from version 8.6.0 before 8.13.10, and from version 8.14.0 before 8.18.2.
How severe is CVE-2021-39121?: CVE-2021-39121 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-39121 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39121?: CVE-2021-39121 primarily affects Atlassian Data Center. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39121?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39121 published?: CVE-2021-39121 was published on 2021-09-08 and last updated on 2026-06-17.

References

https://jira.atlassian.com/browse/JRASERVER-72715

Affected products (4)

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

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