What is CVE-2019-20372?

CVE-2019-20372 is a medium-severity vulnerability in Apple Xcode, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 5.3/10. Published 2020-01-09.

How severe is CVE-2019-20372?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Is CVE-2019-20372 known to be exploited?

20 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apple Xcode

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 read unauthorized web pages in environments where NGINX is being fronted by a load balancer.

Vulnerability class: HTTP Request Smuggling

Published 2020-01-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.150 (96.7th percentile), scored 2026-10-18.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.150 · newest: 0.150 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

Public proof-of-concept exploits

References

bertjwregeer.keybase.pub/2019-12-10 - error_page request smuggling.pdf (Exploit, Third Party Advisory, Mitigation)
nginx.org/en/CHANGES (Release Notes, Mitigation, Vendor Advisory)
duo.com/docs/dng-notes (Third Party Advisory, Release Notes)
github.com/kubernetes/ingress-nginx/pull/4859 (Patch, Third Party Advisory)
github.com/nginx/nginx/commit/c1be55f97211d38b69ac0c2027e6812ab8b1b94e (Patch, Vendor Advisory)
usn.ubuntu.com/4235-1/ (vendor-advisory, Third Party Advisory)
usn.ubuntu.com/4235-2/ (vendor-advisory, Third Party Advisory)
security.netapp.com/advisory/ntap-20200127-0003/ (Third Party Advisory)
lists.opensuse.org/opensuse-security-announce/2020-02/msg00013.html (vendor-advisory, Mailing List, Third Party Advisory)
support.apple.com/kb/HT212818 (Third Party Advisory)

Frequently asked questions

What is CVE-2019-20372?: CVE-2019-20372 is a medium-severity vulnerability in Apple Xcode, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 5.3/10. Published 2020-01-09.
How severe is CVE-2019-20372?: Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2019-20372 known to be exploited?: 20 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.