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No exploitation reportedFix available

CVE-2020-11993

No exploitation reported by the sources we read.

  • Published2020-08-07
  • Fixed in2.4.44
  • WeaknessCWE-444

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-08-0716:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-11993?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-11993?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Apache HTTP Server
BranchAffectedFixed in
2.4≥ 2.4.20, < 2.4.442.4.44
Canonical ubuntu linux
BranchAffectedFixed in
16.4= 16.04no fix published
18.4= 18.04no fix published
20.4= 20.04no fix published
Oracle instantis enterprisetrack
BranchAffectedFixed in
17.1= 17.1no fix published
17.2= 17.2no fix published
17.3= 17.3no fix published

10 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • apacheMageia:7all versions · fixed in 2.4.46-1.mga7
  • apache2Ubuntu:20.04:LTSall versions · fixed in 2.4.41-4ubuntu3.1
  • apache2Ubuntu:18.04:LTSall versions · fixed in 2.4.29-1ubuntu4.14
  • apache2Ubuntu:16.04:LTSall versions · fixed in 2.4.18-2ubuntu3.17
  • apache2SUSE:OpenStack Cloud Crowbar 9all versions · fixed in 2.4.23-29.63.1
  • apache2SUSE:OpenStack Cloud Crowbar 8all versions · fixed in 2.4.23-29.63.1
  • apache2SUSE:OpenStack Cloud 9all versions · fixed in 2.4.23-29.63.1
  • apache2SUSE:OpenStack Cloud 8all versions · fixed in 2.4.23-29.63.1

93 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-11993 Red Hat Product Security361 products fixed · 3 known affected

    httpd: mod_http2 concurrent pool usage

    jbcs-httpd24 as a component of Red Hat JBoss Enterprise Web Server 2 · jbcs-httpd24-runtime as a component of Red Hat JBoss Enterprise Web Server 2 · jbcs-httpd24.src as a component of Red Hat JBoss Enterprise Web Server 2

  • RHSA-2021:1809 Red Hat Product Security85 products fixed

    Red Hat Security Advisory: httpd:2.4 security, bug fix, and enhancement update

  • RHBA-2020:5280 Red Hat Product Security88 products fixed

    Red Hat Bug Fix Advisory: httpd24 bug fix and enhancement update

  • RHSA-2020:4384 Red Hat Product Security187 products fixed

    Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP5 security update

  • RHSA-2020:4383 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP5 security update

Full record on NVD

Fix

  1. Update Apache HTTP Server to 2.4.44
  2. Vendor fix Red Hat Product Security RHSA-2021:1809 · 85 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 After installing the updated packages, the httpd daemon will be restarted automatically.
  3. Vendor fix Red Hat Product Security RHBA-2020:5280 · 88 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2020:4383 · 1 productBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. The References section of this erratum contains a download link for the update. You must be logged in to download the update.
  5. No fix planned, says the vendor Red Hat Product Security CVE-2020-11993 · 3 productsOut of support scope

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.04.3read 2026-10-23
  • NVDweakness (CWE)CWE-444read 2026-10-23
  • FIRST EPSSEPSS score56.4 %read 2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-08-07
Last Modified
2026-06-17
NVD status
Analyzed

Frequently asked questions

What is CVE-2020-11993?

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.

Is CVE-2020-11993 actively exploited?

Active exploitation of CVE-2020-11993 has not been confirmed. Its EPSS score was 56.4% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-11993?

CVE-2020-11993 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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