How severe is CVE-2021-39126?

CVE-2021-39126 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-39126 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39126?

CVE-2021-39126 primarily affects Atlassian Jira 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-2021-39126?

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

When was CVE-2021-39126 published?

CVE-2021-39126 was published on 2021-10-21 and last updated on 2026-06-17.

CVE-2021-39126

CVE-2021-39126 is a medium-severity vulnerability in Atlassian Jira Data Center with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-352.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-352
Affected product: Atlassian Jira Data Center
Published: 2021-10-21
Last modified: 2026-06-17

Description

Affected versions of Atlassian Jira Server and Data Center allow remote attackers to modify various resources via a Cross-Site Request Forgery (CSRF) vulnerability, following an Information Disclosure vulnerability in the referrer headers which discloses a user's CSRF token. The affected versions are before version 8.5.10, and from version 8.6.0 before 8.13.1.

Frequently asked questions

What is CVE-2021-39126?: Affected versions of Atlassian Jira Server and Data Center allow remote attackers to modify various resources via a Cross-Site Request Forgery (CSRF) vulnerability, following an Information Disclosure vulnerability in the referrer headers which discloses a user's CSRF token. The affected versions are before version 8.5.10, and from version 8.6.0 before 8.13.1.
How severe is CVE-2021-39126?: CVE-2021-39126 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-39126 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39126?: CVE-2021-39126 primarily affects Atlassian Jira 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-2021-39126?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39126 published?: CVE-2021-39126 was published on 2021-10-21 and last updated on 2026-06-17.

References

https://jira.atlassian.com/browse/JRASERVER-71806

Affected products (2)

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

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