`CVE-2018-11763` Apache HTTP Server

Affected software	Apache HTTP Server
Severity	5.9 Medium CVSS 3.0 2 scores
Published	25 Sep 2018
Updated	17 Jun 2026

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.

Exploitation status

Exploited

Real-world exploitation reported by VulnCheck KEV. CISA has not confirmed it.

CISA KEV not listed
VulnCheck KEV listed Exploitation reported in the wild. 1 citation · earliest 2022-02-22.
CISA Vulnrichment no assessment published
Indexed PoC none indexed
EPSS 51% chance in 30 days A model's forecast, not a report of exploitation. Higher than 99% of all scored CVEs.

VulnCheck KEV

Exploitation evidence from VulnCheck Known Exploited Vulnerabilities (VulnCheck KEV), used under VulnCheck's community terms. View CVE-2018-11763 in VulnCheck (free account).

Evidence	Source	Detail	Date
Reported exploitation	trendmicro.com	/en_us/research/22/b/recent-cyberattacks-open-source-web-servers.html	2022-02-22

Evidence

Source

Detail

Date

Reported exploitation

trendmicro.com

/en_us/research/22/b/recent-cyberattacks-open-source-web-servers.html

2022-02-22

Waratek protection

Outside Waratek scope

A Java vulnerability, but not one Waratek protects. It affects only Java on a user's desktop (applets, Web Start, JavaFX, the installer), sits in a product the Waratek agent can't be installed into, or is in a package we don't expect in business applications. The decision below says which.

Protection none
Action not pursued none
Review human Researcher
Record active

Decided by	Manual classification of this CVE in the legacy dataset
Finding	A manual classification set this CVE's status to Outside Waratek scope, but the CVE names a tracked product.

Decided by

Manual classification of this CVE in the legacy dataset

Finding

A manual classification set this CVE's status to Outside Waratek scope, but the CVE names a tracked product.

CVSS

5.9 MEDIUM v3.0 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

Version Score Band Vector Assigner Type

CVSS 3.0 5.9 MEDIUM CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary published

CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:N/I:N/A:P NVD Primary

Version	Score	Band	Vector	Assigner	Type
CVSS 3.0	5.9	MEDIUM	`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`	NVD	Primary	published
CVSS 2.0	4.3	none	`AV:N/AC:M/Au:N/C:N/I:N/A:P`	NVD	Primary

Affected software and releases

Oracle advisories

Advisory	Type	Quarter	Products Oracle names in its risk matrix
Oracle Critical Patch Update April 2019 ↗	CPU	2019-Q2	Oracle Construction and Engineering Suite / Core (Apache HTTP Server) (17.1, 17.2, 17.3) Oracle Enterprise Manager Products Suite / Networking (Apache HTTP Server) (12.3.3) Oracle Hospitality Applications / Base (Apache HTTP Server) (4.2.0, 4.2.1) Oracle Retail Applications / Point of Sale (Apache HTTP Server) (7.0, 7.1) Oracle Retail Applications / Xstore Office (Apache HTTP Server) (7.0, 7.1)
Oracle Critical Patch Update January 2019 ↗	CPU	2019-Q1	Oracle Virtualization / Web Server (Apache HTTP Server) (5.4)

Advisory

Type

Quarter

Products Oracle names in its risk matrix

Oracle Critical Patch Update April 2019 ↗

CPU

2019-Q2

Oracle Construction and Engineering Suite / Core (Apache HTTP Server) (17.1, 17.2, 17.3)
Oracle Enterprise Manager Products Suite / Networking (Apache HTTP Server) (12.3.3)
Oracle Hospitality Applications / Base (Apache HTTP Server) (4.2.0, 4.2.1)
Oracle Retail Applications / Point of Sale (Apache HTTP Server) (7.0, 7.1)
Oracle Retail Applications / Xstore Office (Apache HTTP Server) (7.0, 7.1)

Oracle Critical Patch Update January 2019 ↗

CPU

2019-Q1

Oracle Virtualization / Web Server (Apache HTTP Server) (5.4)

Oracle components and versions

Family	Component	Versions, as Oracle lists them	Read as
Oracle Construction and Engineering Suite	Core (Apache HTTP Server)	17.1, 17.2, 17.3	17.1 · 17.2 · 17.3
Oracle Enterprise Manager Products Suite	Networking (Apache HTTP Server)	12.3.3	12.3.3
Oracle Hospitality Applications	Base (Apache HTTP Server)	4.2.0, 4.2.1	4.2.0 · 4.2.1
Oracle Retail Applications	Point of Sale (Apache HTTP Server)	7.0, 7.1	7.0 · 7.1
Oracle Retail Applications	Xstore Office (Apache HTTP Server)	7.0, 7.1	7.0 · 7.1
Oracle Virtualization	Web Server (Apache HTTP Server)	5.4	5.4

Family

Component

Versions, as Oracle lists them

Read as

Oracle Construction and Engineering Suite

Core (Apache HTTP Server)

17.1, 17.2, 17.3

17.1 · 17.2 · 17.3

Oracle Enterprise Manager Products Suite

Networking (Apache HTTP Server)

12.3.3

Oracle Hospitality Applications

Base (Apache HTTP Server)

4.2.0, 4.2.1

4.2.0 · 4.2.1

Oracle Retail Applications

Point of Sale (Apache HTTP Server)

7.0, 7.1

7.0 · 7.1

Oracle Retail Applications

Xstore Office (Apache HTTP Server)

7.0, 7.1

7.0 · 7.1

Oracle Virtualization

Web Server (Apache HTTP Server)

5.4

Products and versions

9 products, 17 version entries

Source	Vendor	Product	Scheme	Affected versions
nvd	apache	http server	generic	≥ 2.4.17 and ≤ 2.4.34
nvd	canonical	ubuntu linux	generic	18.04
nvd	netapp	storage automation store	generic	any version
nvd	oracle	enterprise manager ops center	generic	12.3.3
nvd	oracle	hospitality guest access	generic	4.2.0 · 4.2.1
nvd	oracle	instantis enterprisetrack	generic	17.1 · 17.2 · 17.3
nvd	oracle	retail xstore point of service	generic	7.0 · 7.1
nvd	oracle	secure global desktop	generic	5.4
nvd	redhat	enterprise linux	generic	6.0 · 7.0 · 7.4 · 7.5 · 7.6

Source

Vendor

Product

Scheme

Affected versions

nvd

apache

http server

generic

≥ 2.4.17 and ≤ 2.4.34

nvd

canonical

ubuntu linux

generic

18.04

nvd

netapp

storage automation store

generic

any version

nvd

oracle

enterprise manager ops center

generic

12.3.3

nvd

oracle

hospitality guest access

generic

4.2.0 · 4.2.1

nvd

oracle

instantis enterprisetrack

generic

17.1 · 17.2 · 17.3

nvd

oracle

retail xstore point of service

generic

7.0 · 7.1

nvd

oracle

secure global desktop

generic

5.4

nvd

redhat

enterprise linux

generic

6.0 · 7.0 · 7.4 · 7.5 · 7.6

Earlier manual review

A reviewer classified this CVE in an older dataset. We kept the labels and products below, but not the reviewer's reasoning.

## Manual Classification Context **Labels:** NETWORKING (APACHE HTTP SERVER), HTTP, POINT OF SALE (APACHE HTTP SERVER), CORE (APACHE HTTP SERVER), BASE (APACHE HTTP SERVER), NO AUTH REMOTE EXPLOIT, WEB SERVER (APACHE HTTP SERVER), XSTORE OFFICE (APACHE HTTP SERVER) **Products:** HTTPD, INSTANTIS ENTERPRISETRACK, ORACLE RETAIL APPLICATIONS, ENTERPRISE MANAGER OPS CENTER, ORACLE SECURE GLOBAL DESKTOP (SGD), ORACLE CONSTRUCTION AND ENGINEERING SUITE, ORACLE VIRTUALIZATION, ORACLE HOSPITALITY APPLICATIONS, ORACLE HOSPITALITY GUEST ACCESS, ORACLE ENTERPRISE MANAGER PRODUCTS SUITE, ORACLE RETAIL XSTORE POINT OF SERVICE

References

URL	Tags
http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00030.html
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00056.html
http://www.securityfocus.com/bid/105414	Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1041713	Third Party Advisory, VDB Entry
https://access.redhat.com/errata/RHSA-2018:3558	Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0366	Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:0367	Third Party Advisory
https://httpd.apache.org/security/vulnerabilities_24.html	Vendor Advisory
https://lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd65286ba%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/84a3714f0878781f6ed84473d1a503d2cc382277e100450209231830%40%3Ccvs.httpd.apache.org%3E

URL

Timeline

Published	2018-09-25	By the CVE Program.
VulnCheck KEV: earliest evidence	2022-02-22	Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.
NVD record modified	2026-06-17	NVD's own last-modified date for this record.

Published

2018-09-25

By the CVE Program.

VulnCheck KEV: earliest evidence

2022-02-22

Date of the oldest evidence of exploitation in VulnCheck KEV's record. VulnCheck does not publish the date it listed the CVE.

NVD record modified

2026-06-17

NVD's own last-modified date for this record.

How VRT decided (5 of 24 rules ran)

5 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file no match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no match An ARMR security-rule template on disk for this CVE

4 manual-classification no match A researcher's recorded decision for this specific CVE

5 manual classification decided it matched Outside Waratek scope Found in legacy manual classifications

6 non-java-upstream not reached A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component not reached The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side not reached Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven not reached An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead

10 cna-maven-package not reached An affected Maven artifact named by the CNA itself

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint not reached A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

18 open-source-maven not reached The affected package being open source on Maven, so the fix can be read

19 poc-derivable not reached An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit not reached Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

21 secure-rule-match not reached A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc not reached Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold not reached Medium or Low severity, no CISA or VulnCheck KEV listing, no PoC clearing the evidence bar, no CISA verdict, no Oracle advisory

24 no-exploit-published not reached Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all

NVD ↗ · CVE.org ↗