What’s Vulnerable › Vulnerabilities

CVE-2024-24791: Denial of service due to improper 100-continue handling in net/http

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-07-02 · updated 2026-06-17

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.

Affected products

• Go standard library Net/Http: before 1.21.12; from 1.22.0-0 before 1.22.5 — fixed in 1.21.12, 1.22.5

How to fix

Upgrade to a fixed version: Go standard library Net/Http 1.21.12, 1.22.5. Check the vendor advisory for mitigations.

References

• https://go.dev/cl/591255
• https://go.dev/issue/67555
• https://groups.google.com/g/golang-dev/c/t0rK-qHBqzY/m/6MMoAZkMAgAJ
• https://pkg.go.dev/vuln/GO-2024-2963
• https://go.dev/cl/591255
• https://go.dev/issue/67555
• https://groups.google.com/g/golang-dev/c/t0rK-qHBqzY/m/6MMoAZkMAgAJ
• https://pkg.go.dev/vuln/GO-2024-2963
• https://security.netapp.com/advisory/ntap-20241004-0004/

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