CVE-2024-24791: The net/http HTTP/1.1 client mishandled the case where a server responds to a request with an "Expect: 100-continue" header with a non-informational (...

Description

The net/http HTTP/1.1 client mishandled the case where a server responds to a request with an "Expect: 100-continue" header with a non-informational (200 or higher) status. This mishandling could leave a client connection in an invalid state, where the next request sent on the connection will fail. An attacker sending a request to a net/http/httputil.ReverseProxy proxy can exploit this mishandling to cause a denial of service by sending "Expect: 100-continue" requests which elicit a non-informational response from the backend. Each such request leaves the proxy with an invalid connection, and causes one subsequent request using that connection to fail.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.41%

69.3th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Jul 2, 2024
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2024-24791?

The net/http HTTP/1.1 client mishandled the case where a server responds to a request with an "Expect: 100-continue" header with a non-informational (200 or higher) status. This mishandling could leave a client connection in an invalid state, where the next request sent on the connection will fail. An attacker sending a request to a net/http/httputil.ReverseProxy proxy can exploit this mishandling to cause a denial of service by sending "Expect: 100-continue" requests which elicit a non-informational response from the backend. Each such request leaves the proxy with an invalid connection, and causes one subsequent request using that connection to fail.

How severe is CVE-2024-24791?

CVE-2024-24791 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.41% probability of exploitation in the next 30 days.

How do I fix CVE-2024-24791?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.