CVE-2018-11763
MediumExploitedIn Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect.
Published Sep 25, 2018 · Updated Sep 23, 2026 · Also known as ALPINE-CVE-2018-11763, DEBIAN-CVE-2018-11763, SUSE-SU-2018:3101-1, SUSE-SU-2018:3582-1, SUSE-SU-2018:3582-2, UBUNTU-CVE-2018-11763, USN-3783-1
Key Facts
Patch immediately- CVE-2018-11763 is a medium-severity vulnerability (CVSS 5.9 v3.1) affecting HTTP Server (Apache), Storage Automation Store (Netapp), Enterprise Manager Ops Center (Oracle) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Feb 22, 2022. No public exploit code is known.
- EPSS estimates a 51% probability of exploitation in the next 30 days.
- Fixed versions are available, including HTTP Server <=2.4.34, apache2 2.4.23-29.27.2, apache2 2.4.23-31.1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
5.9
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
51%
Higher than 98.9% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
None known
Get the full CVE-2018-11763 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections. A possible mitigation is to not enable the h2 protocol.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Feb 22, 2022 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
241 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| HTTP ServerApache | >= 2.4.17 to 2.4.34 | 2.4.34 |
| Storage Automation StoreNetapp | See advisory | n/a |
| Enterprise Manager Ops CenterOracle | 12.3.3 | n/a |
| Hospitality Guest AccessOracle | 4.2.0, 4.2.1 | n/a |
| Instantis EnterprisetrackOracle | 17.1, 17.2, 17.3 | n/a |
Patched Releases
HTTP Server
<=2.4.34
apache2
2.4.23-29.27.2, 2.4.23-31.1, 2.4.29-1ubuntu4.4, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1, 2.4.35-1, 2.4.35-r0
apache2-devel
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1
apache2-doc
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1
apache2-event
2.4.23-31.1, 2.4.33-lp150.2.6.1
apache2-example-pages
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-lp150.2.6.1
apache2-prefork
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1
apache2-utils
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1
apache2-worker
2.4.23-29.27.2, 2.4.23-31.1, 2.4.33-3.6.1, 2.4.33-lp150.2.6.1
httpd
2.4.37-1.amzn2.0.1, 2.4.37-1.ph1, NA
httpd-devel
2.4.37-1.amzn2.0.1
httpd-filesystem
2.4.37-1.amzn2.0.1
httpd-manual
2.4.37-1.amzn2.0.1
httpd-tools
2.4.37-1.amzn2.0.1
httpd24
2.4.37-1.83.amzn1
httpd24-curl
0:7.61.1-1.el6, 0:7.61.1-1.el7
httpd24-devel
2.4.37-1.83.amzn1
httpd24-httpd
0:2.4.34-7.el6, 0:2.4.34-7.el7
httpd24-manual
2.4.37-1.83.amzn1
httpd24-nghttp2
0:1.7.1-7.el6, 0:1.7.1-7.el7
httpd24-tools
2.4.37-1.83.amzn1
jbcs-httpd24
0:1-6.jbcs.el6, 0:1-6.jbcs.el7
jbcs-httpd24-apache-commons-daemon-jsvc
1:1.1.0-3.redhat_2.jbcs.el6, 1:1.1.0-3.redhat_2.jbcs.el7
jbcs-httpd24-apr
0:1.6.3-31.jbcs.el6, 0:1.6.3-31.jbcs.el7
jbcs-httpd24-apr-util
0:1.6.1-24.jbcs.el6, 0:1.6.1-24.jbcs.el7
Timeline
Publicly disclosed
Sep 25, 2018
Added to Industry KEV feed
Feb 22, 2022
Last updated
Sep 23, 2026
Weakness Type
- CWE-20 Improper Input Validation
References
- advisoryRHSA-2018:3558
- advisoryRHSA-2019:0366
- advisoryRHSA-2019:0367
- advisoryhttps://bugzilla.suse.com/1109961
- advisoryhttps://httpd.apache.org/security/vulnerabilities_24.html
FAQ
Common Questions.
In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect.
Affected: HTTP Server (Apache) versions >= 2.4.17 to 2.4.34; Storage Automation Store (Netapp); Enterprise Manager Ops Center (Oracle) versions 12.3.3, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Feb 22, 2022.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including HTTP Server <=2.4.34, apache2 2.4.23-29.27.2, apache2 2.4.23-31.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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