CVE-2019-20372: NGINX before 1.17.7, with certain error_page configurations, allows HTTP request smuggling, as demonstrated by

Q: How do I fix CVE-2019-20372?

nginx: upgrade to 1.17.7; xcode: upgrade to 13.0; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2019-20372 being exploited?

CVE-2019-20372 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2019-20372 affect?

CVE-2019-20372 affects nginx, xcode, ubuntu linux. Severity is medium (CVSS 5.3). 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.

Q: How urgent is CVE-2019-20372?

Priority 58/100. EPSS top 3%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

MEDIUM 5.3REMOTEWATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2019-20372 is a medium-severity flaw (CVSS 5.3) affecting nginx, xcode, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

EPSS top 3%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	15.0% (top 3%)
CISA exploited list	No
Weakness	CWE-444
Published	2020-01-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: apple · canonical · f5 · netapp · opensuse

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-01-09 21:15 UTCPublished CVE record published
2026-06-17 02:30 UTCUpdated Record last modified

f5 nginx UPGRADE

Affected: < 1.17.7

Fixed in: 1.17.7

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nginx || rpm -q nginx || nginx --version

2. UPGRADE to 1.17.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nginx

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nginx

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

apple xcode UPGRADE

Affected: < 13.0

Fixed in: 13.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy xcode || rpm -q xcode || xcode --version

2. UPGRADE to 13.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade xcode

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade xcode

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

canonical ubuntu linux MITIGATE

Affected: 14.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

opensuse leap MITIGATE

Affected: 15.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 15.1

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

netapp cloud backup MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cloud-backup || rpm -q cloud-backup || cloud-backup --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-20372?

nginx: upgrade to 1.17.7; xcode: upgrade to 13.0; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-20372 being exploited?

CVE-2019-20372 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-20372 affect?

CVE-2019-20372 affects nginx, xcode, ubuntu linux. Severity is medium (CVSS 5.3). 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.

How urgent is CVE-2019-20372?

Priority 58/100. EPSS top 3%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

nginx vulnerabilities · Ubuntu vulnerabilities · F5 BIG-IP vulnerabilities

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References

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