CVE-2021-36160 | mod_proxy_uwsgi out of bound read

A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive).

Published: 2021-09-16 Last update: 2025-05-01 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-36160 is rated Moderate Risk (62.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.69%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-36160

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-29 3.72% 4.69% +0.97%
2 2026-03-17 4.96% 3.72% -1.25%
3 2026-03-04 4.96%

Full EPSS history (60 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-36160

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-36160

OS Trackers for CVE-2021-36160

vendor priority summary link
alpine CVE-2021-36160: 1 source package rows (apache2); 9 state rows across 9 repos (3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 9, open 0. https://security.alpinelinux.org/vuln/CVE-2021-36160
debian unimportant CVE-2021-36160 unimportant priority: Debian including 2 source packages (apache2, uwsgi), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5, resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-36160
gentoo high CVE-2021-36160: 1 GLSA(s) (202208-20), 2 atom(s) (app-admin/apache-tools, www-servers/apache); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-36160
redhat medium https://access.redhat.com/security/cve/CVE-2021-36160
suse high CVE-2021-36160 severity important: SUSE including 281 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 482 product×package rows across 59 product lines (HPE Helion OpenStack 8, Image SLES15-SP3-EC2-HVM, … (59 product lines)): Known Affected 231, Fixed 160, Known Not Affected 91. https://www.suse.com/security/cve/CVE-2021-36160/
ubuntu medium CVE-2021-36160 medium priority: Ubuntu including 1 source packages (apache2), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): released 5, not-affected 3. https://ubuntu.com/security/CVE-2021-36160

Affected software / configurations for CVE-2021-36160

Vendor Product Version Raw CPE
apache http_server >= 2.4.30, < 2.4.49 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
netapp cloud_backup cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
netapp clustered_data_ontap cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
netapp storagegrid cpe:2.3:a:netapp:storagegrid:-:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_function_cloud_native_environment 1.10.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:1.10.0:*:*:*:*:*:*:*
oracle enterprise_manager_base_platform 13.4.0.0 cpe:2.3:a:oracle:enterprise_manager_base_platform:13.4.0.0:*:*:*:*:*:*:*
oracle enterprise_manager_base_platform 13.5.0.0 cpe:2.3:a:oracle:enterprise_manager_base_platform:13.5.0.0:*:*:*:*:*:*:*
oracle http_server 12.2.1.3.0 cpe:2.3:a:oracle:http_server:12.2.1.3.0:*:*:*:*:*:*:*
oracle http_server 12.2.1.4.0 cpe:2.3:a:oracle:http_server:12.2.1.4.0:*:*:*:*:*:*:*
oracle instantis_enterprisetrack 17.1 cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*
oracle instantis_enterprisetrack 17.2 cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*
oracle instantis_enterprisetrack 17.3 cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*
oracle peoplesoft_enterprise_peopletools 8.58 cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.58:*:*:*:*:*:*:*
oracle zfs_storage_appliance_kit 8.8 cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
broadcom brocade_fabric_operating_system_firmware cpe:2.3:o:broadcom:brocade_fabric_operating_system_firmware:-:*:*:*:*:*:*:*

References for CVE-2021-36160

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