HOME VULNERABILITIESCVE-2020-11993

HIGH

CVE-2020-11993

CWE-444Published: August 7, 2020· Updated: Jun 17, 2026

7.5

CVSS v3.1

Official 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.

Technical Analysis

CVE-2020-11993 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Affected Vendors & Products

Apache1 product(s)

http server

Canonical1 product(s)

ubuntu linux

Debian1 product(s)

debian linux

Fedora1 product(s)

fedora

netapp1 product(s)

clustered data ontap

openSUSE1 product(s)

leap

Oracle7 product(s)

communications element managercommunications session report managercommunications session route managerenterprise manager ops centerhyperion infrastructure technologyinstantis enterprisetrackzfs storage appliance kit

Source: NVD CPE · 19 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://lists.apache.org/thread.html/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r09bb998baee74a2c316446bd1a41ae7f8d7049d09d9ff991471e8775%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r2c6083f6a2027914a0f5b54e2a1f4fa98c03f8693b58460911818255%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r3c5c3104813c1c5508b55564b66546933079250a46ce50eee90b2e36%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r5debe8f82728a00a4a68bc904dd6c35423bdfc8d601cfb4579f38bf1%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r623de9b2b2433a87f3f3a15900419fc9c00c77b26936dfea4060f672%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r9e9f1a7609760f0f80562eaaec2aa3c32d525c3e0fca98b475240c71%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rdf3e5d0a5f5c3d90d6013bccc6c4d5af59cf1f8c8dea5d9a283d13ce%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rf71eb428714374a6f9ad68952e23611ec7807b029fd6a1b4f5f732d9%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r09bb998baee74a2c316446bd1a41ae7f8d7049d09d9ff991471e8775%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r2c6083f6a2027914a0f5b54e2a1f4fa98c03f8693b58460911818255%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r3c5c3104813c1c5508b55564b66546933079250a46ce50eee90b2e36%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r5debe8f82728a00a4a68bc904dd6c35423bdfc8d601cfb4579f38bf1%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r623de9b2b2433a87f3f3a15900419fc9c00c77b26936dfea4060f672%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r9e9f1a7609760f0f80562eaaec2aa3c32d525c3e0fca98b475240c71%40%3Cdev.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rdf3e5d0a5f5c3d90d6013bccc6c4d5af59cf1f8c8dea5d9a283d13ce%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E

PATCHhttps://lists.apache.org/thread.html/rf71eb428714374a6f9ad68952e23611ec7807b029fd6a1b4f5f732d9%40%3Ccvs.httpd.apache.org%3E

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-08/msg00068.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-08/msg00071.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00081.html

ADVISORYhttp://packetstormsecurity.com/files/160393/Apache-2-HTTP2-Module-Concurrent-Pool-Usage.html

ADVISORYhttps://httpd.apache.org/security/vulnerabilities_24.html#CVE-2020-11993

ADVISORYhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NKWG2EXAQQB6LMLATKZ7KLSRGCSHVAN/

ADVISORYhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVFDBVM6E3JF3O7RYLRPRCH3RDRHJJY/

ADVISORYhttps://security.gentoo.org/glsa/202008-04

ADVISORYhttps://security.netapp.com/advisory/ntap-20200814-0005/

ADVISORYhttps://usn.ubuntu.com/4458-1/

ADVISORYhttps://www.debian.org/security/2020/dsa-4757

ADVISORYhttps://www.oracle.com/security-alerts/cpujan2021.html

ADVISORYhttps://www.oracle.com/security-alerts/cpuoct2020.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-08/msg00068.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-08/msg00071.html

ADVISORYhttp://lists.opensuse.org/opensuse-security-announce/2020-10/msg00081.html

ADVISORYhttp://packetstormsecurity.com/files/160393/Apache-2-HTTP2-Module-Concurrent-Pool-Usage.html

ADVISORYhttps://httpd.apache.org/security/vulnerabilities_24.html#CVE-2020-11993

ADVISORYhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4NKWG2EXAQQB6LMLATKZ7KLSRGCSHVAN/

ADVISORYhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVFDBVM6E3JF3O7RYLRPRCH3RDRHJJY/

ADVISORYhttps://security.gentoo.org/glsa/202008-04

ADVISORYhttps://security.netapp.com/advisory/ntap-20200814-0005/

ADVISORYhttps://usn.ubuntu.com/4458-1/

ADVISORYhttps://www.debian.org/security/2020/dsa-4757

ADVISORYhttps://www.oracle.com/security-alerts/cpujan2021.html

ADVISORYhttps://www.oracle.com/security-alerts/cpuoct2020.html

All References (52)

→

http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00068.htmlMailing List · Third Party Advisory

→

http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00071.htmlMailing List · Third Party Advisory

→

http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00081.htmlMailing List · Third Party Advisory

→

http://packetstormsecurity.com/files/160393/Apache-2-HTTP2-Module-Concurrent-Pool-Usage.htmlExploit · Third Party Advisory · VDB Entry

→

https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2020-11993Vendor Advisory

→

https://lists.apache.org/thread.html/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r09bb998baee74a2c316446bd1a41ae7f8d7049d09d9ff991471e8775%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r2c6083f6a2027914a0f5b54e2a1f4fa98c03f8693b58460911818255%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r3c5c3104813c1c5508b55564b66546933079250a46ce50eee90b2e36%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r5debe8f82728a00a4a68bc904dd6c35423bdfc8d601cfb4579f38bf1%40%3Cdev.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r623de9b2b2433a87f3f3a15900419fc9c00c77b26936dfea4060f672%40%3Cdev.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r9e9f1a7609760f0f80562eaaec2aa3c32d525c3e0fca98b475240c71%40%3Cdev.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3EPatch

→

https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3EPatch

Quick Facts

CVE IDCVE-2020-11993

CVSS Score7.5 / 10

SeverityHIGH

WeaknessCWE-444

CISA KEVNo

Affected7 vendor(s)

PublishedAug 7, 2020

Related CVEs (CWE-444)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2020-11993 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.

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