CVE-2020-11100

Name: CVE-2020-11100
Creator: NVD / NIST
Published: 2020-04-02T15:15:17.483+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 60.73%

Last modified Jun 17, 2026

CVE-2020-11100 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.. EPSS estimates a 60.73% chance of exploitation in the next 30 days.

Description

In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

60.73%

99.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Haproxy	Haproxy	>= 1.8.0, < 2.1.4
Debian	Debian Linux	10.0
Redhat	Openshift Container Platform	3.11
Redhat	Openshift Container Platform	4.0
Fedoraproject	Fedora	30
Fedoraproject	Fedora	31
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	19.10
Opensuse	Leap	15.1

References

http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00002.htmlMailing List, Third Party Advisory
http://packetstormsecurity.com/files/157323/haproxy-hpack-tbl.c-Out-Of-Bounds-Write.htmlThird Party Advisory, VDB Entry
http://www.haproxy.orgVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1819111Issue Tracking, Third Party Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1168023Issue Tracking, Third Party Advisory
https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=5dfc5d5cd0d2128d77253ead3acf03a421ab5b88
https://lists.debian.org/debian-security-announce/2020/msg00052.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/264C7UL3X7L7QE74ZJ557IOUFS3J4QQC/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNW5RZLIX7LOXRLV7WMHX22CI43XSXKW/
https://security.gentoo.org/glsa/202012-22Third Party Advisory
https://usn.ubuntu.com/4321-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4649Third Party Advisory
https://www.haproxy.org/download/2.1/src/CHANGELOGRelease Notes, Vendor Advisory
https://www.mail-archive.com/haproxy%40formilux.org/msg36876.html
http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00002.htmlMailing List, Third Party Advisory
http://packetstormsecurity.com/files/157323/haproxy-hpack-tbl.c-Out-Of-Bounds-Write.htmlThird Party Advisory, VDB Entry
http://www.haproxy.orgVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1819111Issue Tracking, Third Party Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1168023Issue Tracking, Third Party Advisory
https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=5dfc5d5cd0d2128d77253ead3acf03a421ab5b88
https://lists.debian.org/debian-security-announce/2020/msg00052.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/264C7UL3X7L7QE74ZJ557IOUFS3J4QQC/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MNW5RZLIX7LOXRLV7WMHX22CI43XSXKW/
https://security.gentoo.org/glsa/202012-22Third Party Advisory
https://usn.ubuntu.com/4321-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4649Third Party Advisory
https://www.haproxy.org/download/2.1/src/CHANGELOGRelease Notes, Vendor Advisory
https://www.mail-archive.com/haproxy%40formilux.org/msg36876.html

Timeline

Published: Apr 2, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-11100?

How severe is CVE-2020-11100?

CVE-2020-11100 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 60.73% probability of exploitation in the next 30 days.

How do I fix CVE-2020-11100?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-11100?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST