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CVE-2021-36160

59
FAUCET Score

CVE-2021-36160 is a denial-of-service vulnerability affecting Apache HTTP Server versions 2.4.30 to 2.4.48, specifically within the mod_proxy_uwsgi module. A specially crafted request URI-path can lead to an out-of-bounds read, causing the server to crash. Rated with a CVSS score of 7.5 (High), this vulnerability is remotely exploitable with low attack complexity and no user interaction required, resulting in a complete loss of availability. There is no public exploit code available (Metasploit, Nuclei, ExploitDB), and it is not listed in CISA's KEV catalog, though it has received some community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.4.30, < 2.4.49CPE matchmatch criteria
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
35CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
62.89%
Probability of exploitation in next 30 days
EPSS Percentile
99.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.6289 is in the 98th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (11)

apachepatch availablevia llm_extracted
Fixed in: 2.4
microsoftpatch availablevia msrc
Product: 16886-16820Fixed in: 2.4.49-1
microsoftpatch availablevia msrc
Product: cbl2 httpd 2.4.52-1 on CBL Mariner 2.0Fixed in: 2.4.52-1
microsoftpatch availablevia msrc
Product: cm1 httpd 2.4.49-1 on CBL Mariner 1.0Fixed in: 2.4.49-1
microsoftpatch availablevia msrc
Product: 17030-16823Fixed in: 2.4.52-1
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Text-Only JBCSFixed in: jbcs-httpd24-httpd
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: httpd24-httpd-0:2.4.34-23.el7.5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: httpd:2.4-8060020220321163517.d63f516d
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services on RHEL 7Fixed in: jbcs-httpd24-httpd-0:2.4.51-28.el7jbcs
View patch
redhatpatch availablevia redhat_api
Product: JBoss Core Services for RHEL 8Fixed in: jbcs-httpd24-httpd-0:2.4.51-28.el8jbcs
View patch

Vendor Advisories (5)

apachellm-apache-f398f8ed28802aa3LOW

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

Mar 2, 2026
apachellm-apache-a7a91ec4c0e9421dHIGH

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

Dec 10, 2025
redhatCVE-2021-36160Moderate

httpd: mod_proxy_uwsgi: out-of-bounds read via a crafted request uri-path

Sep 16, 2021
microsoft2021-Sep/CVE-2021-36160Important

mod_proxy_uwsgi out of bound read

Sep 14, 2021
apachellm-apache-684e4d0003611bd4LOW

Apache HTTP Server 2.4 vulnerabilities - The Apache HTTP Server Project

References

httpd.apache.org / security/vulnerabilities_24.html
Release NotesVendor Advisory
lists.apache.org / thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r73260f6ba9fb52e43d860905fc90462ba5a814afda2d011f32bbd41c%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r7f2746e916ed370239bc1a1025e5ebbf345f79df9ea0ea39e44acfbb%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/r94a61a1517133a19dcf40016e87454ea86e355d06a0cec4c778530f3%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/ra1c05a392587bfe34383dffe1213edc425de8d4afc25b7cefab3e781%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/ra87a69d0703d09dc52b86e32b08f8d7327af10acdd5f577a4e82596a%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/rb2341c8786d0f9924f5b666e82d8d170b4804f50a523d750551bef1a%40%3Cbugs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/re4162adc051c1a0a79e7a24093f3776373e8733abaff57253fef341d%40%3Ccvs.httpd.apache.org%3E
Patch
lists.apache.org / thread.html/ree7519d71415ecdd170ff1889cab552d71758d2ba2904a17ded21a70%40%3Ccvs.httpd.apache.org%3E
Patch
lists.debian.org / debian-lts-announce/2021/09/msg00016.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2021/10/msg00016.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R
Third Party Advisory
security.gentoo.org / glsa/202208-20
Third Party Advisory
security.netapp.com / advisory/ntap-20211008-0004
Third Party Advisory
tools.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
Third Party Advisory
debian.org / security/2021/dsa-4982
Third Party Advisory
oracle.com / security-alerts/cpuapr2022.html
PatchThird Party Advisory
oracle.com / security-alerts/cpujan2022.html
PatchThird Party Advisory