How severe is CVE-2019-20372?

CVE-2019-20372 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2019-20372 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20372?

CVE-2019-20372 primarily affects F5 Nginx. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-20372?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-20372 published?

CVE-2019-20372 was published on 2020-01-09 and last updated on 2026-06-17.

CVE-2019-20372

CVE-2019-20372 is a medium-severity vulnerability in F5 Nginx with a CVSS 3.x base score of 5.3. Its EPSS exploit-prediction score of 15% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-444.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 4.3
EPSS exploit prediction: 15% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-444
Affected product: F5 Nginx
Published: 2020-01-09
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2019-20372?: CVE-2019-20372 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2019-20372 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 15% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20372?: CVE-2019-20372 primarily affects F5 Nginx. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-20372?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-20372 published?: CVE-2019-20372 was published on 2020-01-09 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*
cpe:2.3:a:apple:xcode:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*

More vulnerabilities in F5 Nginx

CVE-2017-20005 — Critical (CVSS 9.8): NGINX before 1.13.6 has a buffer overflow for years that exceed four digits, as demonstrated by a file with a…
CVE-2016-0746 — Critical (CVSS 9.8): Use-after-free vulnerability in the resolver in nginx 0.6.18 through 1.8.0 and 1.9.x before 1.9.10 allows remote…
CVE-2009-3555 — Critical (CVSS 9.8): The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft Internet Information Services…
CVE-2016-1247 — High (CVSS 7.8): The nginx package before 1.6.2-5+deb8u3 on Debian jessie, the nginx packages before 1.4.6-1ubuntu3.6 on Ubuntu 14.04…
CVE-2021-23017 — High (CVSS 7.7): A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from…
CVE-2023-44487 — High (CVSS 7.5): The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset…

All CVEs affecting F5 Nginx →

Other CWE-444 (HTTP Request/Response Smuggling) vulnerabilities

CVE-2025-1867 — Critical (CVSS 10.0): Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in ithewei libhv allows…
CVE-2022-22536 — Critical (CVSS 10.0): SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53…
CVE-2018-3907 — Critical (CVSS 10.0): An exploitable vulnerability exists in the REST parser of video-core's HTTP server of the Samsung SmartThings Hub…
CVE-2025-55315 — Critical (CVSS 9.9): Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized…
CVE-2020-15049 — Critical (CVSS 9.9): An issue was discovered in http/ContentLengthInterpreter.cc in Squid before 4.12 and 5.x before 5.0.3. A Request…
CVE-2026-13763 — Critical (CVSS 9.8): Inconsistent interpretation of HTTP/2 requests in AWS Application Load Balancer with AWS WAF enabled might allow remote…

Browse all CWE-444 (HTTP Request/Response Smuggling) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

114.67.252.10 (ipv4-addr)
203.193.147.75 (ipv4-addr)
42.200.66.164 (ipv4-addr)
24.122.136.94 (ipv4-addr)
201.186.40.250 (ipv4-addr)
187.72.239.221 (ipv4-addr)
180.76.98.88 (ipv4-addr)
139.59.59.165 (ipv4-addr)