CVE-2025-4439Network attack vector

Authenticated XSS via CDN-served Kubernetes proxy

Published Jul 23, 2025 · Updated Feb 26, 2026

Cross-site scripting in GitLab CE/EE 15.10 through 18.0.4, 18.1 through 18.1.2, and 18.2.0 allows remote authenticated users to execute script. GitLab identifies the Kubernetes proxy on instances served through certain content delivery networks, but has not published the faulty operation on untrusted input. Exploitation requires an authenticated account and victim interaction; injected script executes in the victim’s browser context and can read or alter accessible data.

CVSS severity7.7
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in GitLab CE/EE 15.10 through 18.0.4, 18.1 through 18.1.2, and 18.2.0 allows remote authenticated users to execute script. GitLab identifies the Kubernetes proxy on instances served through certain content delivery networks, but has not published the faulty operation on untrusted input. Exploitation requires an authenticated account and victim interaction; injected script executes in the victim’s browser context and can read or alter accessible data.

The record

CVE
CVE-2025-4439
Published
Jul 23, 2025
Updated
Feb 26, 2026
Vendor
GitLab
Product
GitLab
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=15.10 <18.0.5
  2. Affected versionversion=18.1 <18.1.3
  3. Affected versionversion=18.2 <18.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=15.10 <18.0.5; version=18.1 <18.1.3; version=18.2 <18.2.1

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.7GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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