How severe is CVE-2023-3909?

CVE-2023-3909 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 none, integrity none, and availability low.

Is CVE-2023-3909 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-3909?

CVE-2023-3909 primarily affects Gitlab. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-3909?

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

When was CVE-2023-3909 published?

CVE-2023-3909 was published on 2023-11-06 and last updated on 2026-06-17.

CVE-2023-3909

CVE-2023-3909 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-1333.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1333
Affected product: Gitlab
Published: 2023-11-06
Last modified: 2026-06-17

Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.3 before 16.3.6, all versions starting from 16.4 before 16.4.2, all versions starting from 16.5 before 16.5.1. A Regular Expression Denial of Service was possible by adding a large string in timeout input in gitlab-ci.yml file.

Frequently asked questions

What is CVE-2023-3909?: An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.3 before 16.3.6, all versions starting from 16.4 before 16.4.2, all versions starting from 16.5 before 16.5.1. A Regular Expression Denial of Service was possible by adding a large string in timeout input in gitlab-ci.yml file.
How severe is CVE-2023-3909?: CVE-2023-3909 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 none, integrity none, and availability low.
Is CVE-2023-3909 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-3909?: CVE-2023-3909 primarily affects Gitlab. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-3909?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-3909 published?: CVE-2023-3909 was published on 2023-11-06 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:gitlab:gitlab:*:*:*:*:community:*:*:*
cpe:2.3:a:gitlab:gitlab:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:gitlab:gitlab:16.5.0:*:*:*:community:*:*:*
cpe:2.3:a:gitlab:gitlab:16.5.0:*:*:*:enterprise:*:*:*

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