CVE-2026-5173

Q: How do I fix CVE-2026-5173?

Upgrade gitlab to 18.8.9 or later.

Q: Is CVE-2026-5173 being actively exploited?

Not that we know of. CVE-2026-5173 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.43% is the estimated probability that it will be exploited in the next 30 days. That is higher than 35% of all scored CVEs.

Q: How severe is CVE-2026-5173?

CVE-2026-5173 has a CVSS v3 base score of 8.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2026-5173 affect?

Published advisories record a fix for gitlab (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

HIGH

8.5

CVSS v3

NVD

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.9.6 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3 that could have allowed an authenticated user to invoke unintended server-side methods through websocket connections due to improper access control.

CWE-749

How to fix

Remediation Available

gitlabNVD

Affected:>= 16.9.6, < 18.8.9Fixed in:18.8.9CVE-2026-5173derived from NVD

Affected:>= 18.9.0, < 18.9.5Fixed in:18.9.5CVE-2026-5173derived from NVD

Affected:>= 18.10.0, < 18.10.3Fixed in:18.10.3CVE-2026-5173derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Exploit Intelligence

0.43%probability of exploitation in 30 days

35thpercentile

Low risk: more likely to be exploited than 35% of all known CVEs.

References

Vendor Advisory1

about.gitlab.com

Other references1

gitlab.com

Related Vulnerabilities

Other CWE-749 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-34996	High	8.8	82%	-	-
CVE-2010-0738	Medium	5.3	79%	KEV + Ransom	-
CVE-2018-10931	Critical	9.8	68%	-	Fix
CVE-2010-1428	High	7.5	62%	KEV + Ransom	-
CVE-2023-38124	High	8.8	60%	-	Fix
CVE-2006-1547	High	7.5	55%	KEV	Fix

Common questions

How do I fix CVE-2026-5173?

Upgrade gitlab to 18.8.9 or later.

Is CVE-2026-5173 being actively exploited?

Not that we know of. CVE-2026-5173 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.43% is the estimated probability that it will be exploited in the next 30 days. That is higher than 35% of all scored CVEs.

How severe is CVE-2026-5173?

CVE-2026-5173 has a CVSS v3 base score of 8.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-5173 affect?

Published advisories record a fix for gitlab (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-24.