CVE-2025-4600
CVE-2025-4600 is a high-severity vulnerability in Google Application Load Balancer with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 8.7
- EPSS exploit prediction: 0% (8th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-15449
- Weakness: CWE-444
- Affected product: Google Application Load Balancer
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2025-4600?
- CVE-2025-4600 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
- Is CVE-2025-4600 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-4600?
- CVE-2025-4600 affects Google Application Load Balancer. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2025-4600?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2025-4600 have an EU (EUVD) identifier?
- Yes. CVE-2025-4600 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-15449.
- When was CVE-2025-4600 published?
- CVE-2025-4600 was published on 2025-05-16 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:google:application_load_balancer:*:*:*:*:*:*:*:*
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