--- title: "CVE-2020-11993: Apache HTTP Server vulnerability | CubePath" description: "Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and on certain traffic edge patterns, logging statements…" language: en source: https://cubepath.com/security/cve/CVE-2020-11993 --- # CVE-2020-11993: Apache HTTP Server vulnerability | CubePath ## Description Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and on certain traffic edge patterns, logging statements were made on the wrong connection, causing concurrent use of memory pools. Configuring the LogLevel of mod\_http2 above "info" will mitigate this vulnerability for unpatched servers. Official description from the CVE record, published by apache. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2020-11993) ## Key data ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.56600 (56.6% probability) Percentile 99.1% Scores of Nov 10, 2026 Model v2026.06.15 ## Affected products Products listed in the CVE record, as the CNA published them. - Apache HTTP Server - affected: 2.4.20 to 2.4.43 ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [httpd.apache.org/security/vulnerabilities\_24.html](https://httpd.apache.org/security/vulnerabilities%5F24.html#CVE-2020-11993) - [GLSA-202008-04](https://security.gentoo.org/glsa/202008-04) (security.gentoo.org) vendor-advisory - [\[httpd-dev\] 20200808 Security announcements for CVE-2020-9490/CVE-2020-11993 ?](https://lists.apache.org/thread.html/r9e9f1a7609760f0f80562eaaec2aa3c32d525c3e0fca98b475240c71%40%3Cdev.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-dev\] 20200811 Which version fixed the CVE-2020-9490, CVE-2020-11984 and CVE-2020-11993 vulnerabilities?](https://lists.apache.org/thread.html/r5debe8f82728a00a4a68bc904dd6c35423bdfc8d601cfb4579f38bf1%40%3Cdev.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-dev\] 20200811 Re: Which version fixed the CVE-2020-9490, CVE-2020-11984 and CVE-2020-11993 vulnerabilities?](https://lists.apache.org/thread.html/r623de9b2b2433a87f3f3a15900419fc9c00c77b26936dfea4060f672%40%3Cdev.httpd.apache.org%3E) (lists.apache.org) mailing-list - [USN-4458-1](https://usn.ubuntu.com/4458-1/) (usn.ubuntu.com) vendor-advisory - [FEDORA-2020-8122a8daa2](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NKWG2EXAQQB6LMLATKZ7KLSRGCSHVAN/) (lists.fedoraproject.org) vendor-advisory - [FEDORA-2020-b58dc5df38](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVFDBVM6E3JF3O7RYLRPRCH3RDRHJJY/) (lists.fedoraproject.org) vendor-advisory - [openSUSE-SU-2020:1285](http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00068.html) (lists.opensuse.org) vendor-advisory - [openSUSE-SU-2020:1293](http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00071.html) (lists.opensuse.org) vendor-advisory - [DSA-4757](https://www.debian.org/security/2020/dsa-4757) (debian.org) vendor-advisory - [oracle.com/security-alerts/cpuoct2020.html](https://www.oracle.com/security-alerts/cpuoct2020.html) - [security.netapp.com/advisory/ntap-20200814-0005](https://security.netapp.com/advisory/ntap-20200814-0005/) - [openSUSE-SU-2020:1792](http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00081.html) (lists.opensuse.org) vendor-advisory - [oracle.com/security-alerts/cpujan2021.html](https://www.oracle.com/security-alerts/cpujan2021.html) - [packetstormsecurity.com/files/160393/Apache-2-HTTP2-Module-…](http://packetstormsecurity.com/files/160393/Apache-2-HTTP2-Module-Concurrent-Pool-Usage.html) - [\[httpd-cvs\] 20210330 svn commit: r1073139 \[1/13\] - in /websites/staging/httpd/trunk/content: ./ security/json/](https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073143 \[3/3\] - in /websites/staging/httpd/trunk/content: ./ security/](https://lists.apache.org/thread.html/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1888194 \[13/13\] - /httpd/site/trunk/content/security/json/](https://lists.apache.org/thread.html/r09bb998baee74a2c316446bd1a41ae7f8d7049d09d9ff991471e8775%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073140 \[4/4\] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities\_13.html security/vulnerabilities\_20.html security/vulnerabilities\_22.html security/vulnerabilities\_24.html](https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073139 \[13/13\] - in /websites/staging/httpd/trunk/content: ./ security/json/](https://lists.apache.org/thread.html/rdf3e5d0a5f5c3d90d6013bccc6c4d5af59cf1f8c8dea5d9a283d13ce%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073149 \[1/13\] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/](https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073149 \[13/13\] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/](https://lists.apache.org/thread.html/r3c5c3104813c1c5508b55564b66546933079250a46ce50eee90b2e36%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1073171 - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-11984.json security/json/CVE-2020-11993.json security/vulnerabilities\_24.html](https://lists.apache.org/thread.html/rf71eb428714374a6f9ad68952e23611ec7807b029fd6a1b4f5f732d9%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210330 svn commit: r1888228 - in /httpd/site/trunk/content/security/json: CVE-2020-11984.json CVE-2020-11993.json](https://lists.apache.org/thread.html/r2c6083f6a2027914a0f5b54e2a1f4fa98c03f8693b58460911818255%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list - [\[httpd-cvs\] 20210606 svn commit: r1075470 \[4/4\] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities\_13.html security/vulnerabilities\_20.html security/vulnerabilities\_22.html security/vulnerabilities\_24.html](https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E) (lists.apache.org) mailing-list ## Timeline 1. ID reserved Apr 21, 2020 2. Record published Aug 7, 2020 3. Record last updated Aug 4, 2024 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 20:03 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)