#VU24230 Inconsistent interpretation of HTTP requests in nginx - CVE-2019-20372


| Updated: 2025-05-09

Vulnerability identifier: #VU24230

Vulnerability risk: Medium

CVSSv4.0: 5.5 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2019-20372

CWE-ID: CWE-444

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
nginx
Server applications / Web servers

Vendor: NGINX

Description

The vulnerability allows a remote attacker to perform HTTP request smuggling attacks.

The vulnerability exists with certain error_page configurations. A remote attacker can read unauthorized web pages in environments where NGINX is being fronted by a load balancer.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

nginx: 1.5.0, 1.5.1, 1.5.2, 1.5.3, 1.5.4, 1.5.5, 1.5.6, 1.5.7, 1.5.8, 1.5.9, 1.5.10, 1.5.11, 1.5.12, 1.5.13, 1.6.0, 1.6.1, 1.6.2, 1.6.3, 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5, 1.7.6, 1.7.7, 1.7.8, 1.7.9, 1.7.10, 1.7.11, 1.7.12, 1.8.0, 1.8.1, 1.9.0, 1.9.1, 1.9.2, 1.9.3, 1.9.4, 1.9.5, 1.9.6, 1.9.7, 1.9.8, 1.9.9, 1.9.10, 1.9.11, 1.9.12, 1.9.13, 1.9.14, 1.9.15, 1.10.0, 1.10.1, 1.10.2, 1.10.3, 1.11.0, 1.11.1, 1.11.2, 1.11.3, 1.11.4, 1.11.5, 1.11.6, 1.11.7, 1.11.8, 1.11.9, 1.11.10, 1.11.11, 1.11.12, 1.11.13, 1.12.0, 1.12.1, 1.12.2, 1.13.0, 1.13.1, 1.13.2, 1.13.3, 1.13.4, 1.13.5, 1.13.6, 1.13.7, 1.13.8, 1.13.9, 1.13.10, 1.13.11, 1.13.12, 1.14.0, 1.14.1, 1.14.2, 1.15.0, 1.15.1, 1.15.2, 1.15.3, 1.15.4, 1.15.5, 1.15.6, 1.15.7, 1.15.8, 1.15.9, 1.15.10, 1.15.11, 1.15.12, 1.16.0, 1.16.1, 1.17.0, 1.17.1, 1.17.2, 1.17.3, 1.17.4, 1.17.5, 1.17.6


External links
https://nginx.org/en/CHANGES
https://bertjwregeer.keybase.pub/2019-12-10%20-%20error_page%20request%20smuggling.pdf
https://duo.com/docs/dng-notes#version-1.5.4-january-2020
https://github.com/kubernetes/ingress-nginx/pull/4859
https://github.com/nginx/nginx/commit/c1be55f97211d38b69ac0c2027e6812ab8b1b94e


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.


Latest bulletins with this vulnerability