What is CVE-2023-4378?

CVE-2023-4378 is a medium-severity vulnerability in GitLab, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 5.5/10. Published 2023-09-01.

How severe is CVE-2023-4378?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in GitLab

CVE-2023-4378

An issue has been discovered in GitLab CE/EE affecting all versions starting from 11.8 before 16.1.5, all versions starting from 16.2 before 16.2.5, all versions starting from 16.3 before 16.3.1. A malicious Maintainer can, under specific circumstances, leak the sentry token by changing the configured URL in the Sentry error tracking settings page. This was as a result of an incomplete fix for CVE-2022-4365.

Published 2023-09-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (41.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

GitLab — versions 16.3.0, 16.2, 11.8

Weakness classification (CWE)

CWE-201 — Insertion of Sensitive Information into Sent Data

References

gitlab.com/gitlab-org/gitlab/-/issues/422134 (issue-tracking, permissions-required, Broken Link)
hackerone.com/reports/2104591 (Permissions Required, technical-description, exploit)

Frequently asked questions

What is CVE-2023-4378?: CVE-2023-4378 is a medium-severity vulnerability in GitLab, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 5.5/10. Published 2023-09-01.
How severe is CVE-2023-4378?: Medium severity. CVSS v3 base score is 5.5 out of 10.