Vulnerability in Microsoft Asp.net Core 2.3

CVE-2025-55315

Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized attacker to bypass a security feature over a network.

Vulnerability class: HTTP Request Smuggling

EPSS: 0.017 (82.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L/E:U/RL:O/RC:C.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-55315?
CVE-2025-55315 is a critical-severity vulnerability in Microsoft Asp.net Core 2.3, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.9/10. Published 2025-10-14.
How severe is CVE-2025-55315?
Critical severity. CVSS v3 base score is 9.9 out of 10.
Is CVE-2025-55315 known to be exploited?
4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.