What is CVE-2025-4600?

CVE-2025-4600 is a high-severity vulnerability in Google Application Load Balancer, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2025-05-16.

How severe is CVE-2025-4600?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Google Application Load Balancer

CVE-2025-4600

A request smuggling vulnerability existed in the Google Cloud Classic Application Load Balancer due to improper handling of chunked-encoded HTTP requests. This allowed attackers to craft requests that could be misinterpreted by backend servers. The issue was fixed by disallowing stray data after a chunk, and is no longer exploitable. No action is required as Classic Application Load Balancer service after 2025-04-26 is not vulnerable.

Vulnerability class: HTTP Request Smuggling

EPSS: 0.002 (8.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Google Application_load_balancer
Google Cloud Classic Application Load Balancer — versions 0

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

cve-coordination@google.com (Vendor Advisory)

Frequently asked questions

What is CVE-2025-4600?: CVE-2025-4600 is a high-severity vulnerability in Google Application Load Balancer, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2025-05-16.
How severe is CVE-2025-4600?: High severity. CVSS v3 base score is 7.5 out of 10.