How severe is CVE-2021-39889?

CVE-2021-39889 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-2021-39889 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39889?

CVE-2021-39889 affects Gitlab. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39889?

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

When was CVE-2021-39889 published?

CVE-2021-39889 was published on 2021-10-05 and last updated on 2026-06-17.

CVE-2021-39889

CVE-2021-39889 is a medium-severity vulnerability in Gitlab 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. The underlying weakness is classified as CWE-639.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-639
Affected product: Gitlab
Published: 2021-10-05
Last modified: 2026-06-17

Description

In all versions of GitLab EE since version 14.1, due to an insecure direct object reference vulnerability, an endpoint may reveal the protected branch name to a malicious user who makes a crafted API call with the ID of the protected branch.

Frequently asked questions

What is CVE-2021-39889?: In all versions of GitLab EE since version 14.1, due to an insecure direct object reference vulnerability, an endpoint may reveal the protected branch name to a malicious user who makes a crafted API call with the ID of the protected branch.
How severe is CVE-2021-39889?: CVE-2021-39889 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-2021-39889 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39889?: CVE-2021-39889 affects Gitlab. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39889?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39889 published?: CVE-2021-39889 was published on 2021-10-05 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*

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