HTTP Request Smuggling in Google Cloud Classic Application Load Balancer due to Improper Chunked Encoding Validation
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2025-4600
- 2026-10-03 Alias added: GHSA-crqj-898f-x3m2
References
Sources
- CVE-2025-4600 · CVE Program
- CVE-2025-4600 · NVD
- FIRST EPSS
- GHSA-crqj-898f-x3m2 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences