What is CVE-2018-16843?

CVE-2018-16843 is a high-severity vulnerability in Apple Xcode, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2018-11-07.

How severe is CVE-2018-16843?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2018-16843 known to be exploited?

15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Resource exhaustion in Apple Xcode

CVE-2018-16843

nginx before versions 1.15.6 and 1.14.1 has a vulnerability in the implementation of HTTP/2 that can allow for excessive memory consumption. This issue affects nginx compiled with the ngx_http_v2_module (not compiled by default) if the 'http2' option of the 'listen' directive is used in a configuration file.

Vulnerability class: DoS (Denial of Service)

Published 2018-11-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.480 (98.8th percentile), scored 2026-10-19.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.471 · newest: 0.480 · change: +0.009

Affected products

Apple Xcode
F5 nginx
[Unknown] nginx — versions 1.15.6, 1.14.1
Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04
Debian Linux — versions 9.0
openSUSE Leap — versions 15.1

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

Public proof-of-concept exploits

References

www.debian.org/security/2018/dsa-4335 (vendor-advisory, Third Party Advisory)
access.redhat.com/errata/RHSA-2018:3680 (vendor-advisory, Third Party Advisory)
access.redhat.com/errata/RHSA-2018:3681 (vendor-advisory, Third Party Advisory)
www.securityfocus.com/bid/105868 (VDB Entry, Third Party Advisory, vdb-entry)
mailman.nginx.org/pipermail/nginx-announce/2018/000220.html (Mailing List, Vendor Advisory)
www.securitytracker.com/id/1042038 (VDB Entry, Third Party Advisory, vdb-entry)
bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
access.redhat.com/errata/RHSA-2018:3653 (vendor-advisory, Third Party Advisory)
usn.ubuntu.com/3812-1/ (vendor-advisory, Third Party Advisory)
lists.opensuse.org/opensuse-security-announce/2019-09/msg00035.html (vendor-advisory, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2018-16843?: CVE-2018-16843 is a high-severity vulnerability in Apple Xcode, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2018-11-07.
How severe is CVE-2018-16843?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2018-16843 known to be exploited?: 15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.