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CVE-2020-11100

54
FAUCET Score

CVE-2020-11100 describes a heap-based buffer overflow vulnerability in the HPACK decoder of HAProxy versions 1.8 through 2.1.3. A remote attacker can exploit this flaw by sending a specially crafted HTTP/2 request, potentially leading to arbitrary byte writes on the heap. This vulnerability carries a high CVSS score of 8.8, indicating a critical risk with network-based exploitation, low attack complexity, and high impact on confidentiality, integrity, and availability, including the possibility of remote code execution. While the EPSS score suggests a higher-than-average exploitability probability, there is currently no public exploit code available, nor is there evidence of active exploitation or significant community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.8.0, < 2.1.4CPE matchmatch criteria
cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
3.11CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*
4.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
30CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
60.73%
Probability of exploitation in next 30 days
EPSS Percentile
99.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.6073 is in the 99th percentile among its peer group of 17,822 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (8)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: haproxy-0:1.8.15-6.el8_1.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.0 Update Services for SAP SolutionsFixed in: haproxy-0:1.8.15-5.el8_0.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenShift Container Platform 3.11Fixed in: haproxy-0:1.8.23-3.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenShift Container Platform 4.4Fixed in: haproxy-0:2.0.13-3.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-haproxy18-haproxy-0:1.8.17-1.el7.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUSFixed in: rh-haproxy18-haproxy-0:1.8.17-1.el7.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: rh-haproxy18-haproxy-0:1.8.17-1.el7.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUSFixed in: rh-haproxy18-haproxy-0:1.8.17-1.el7.1
View patch

Vendor Advisories (1)

redhatCVE-2020-11100Critical

haproxy: malformed HTTP/2 requests can lead to out-of-bounds writes

Apr 2, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-04/msg00002.html
Mailing ListThird Party Advisory
packetstormsecurity.com / files/157323/haproxy-hpack-tbl.c-Out-Of-Bounds-Write.html
Third Party AdvisoryVDB Entry
bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
bugzilla.suse.com / show_bug.cgi
Issue TrackingThird Party Advisory
git.haproxy.org
lists.debian.org / debian-security-announce/2020/msg00052.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/264C7UL3X7L7QE74ZJ557IOUFS3J4QQC
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/MNW5RZLIX7LOXRLV7WMHX22CI43XSXKW
security.gentoo.org / glsa/202012-22
Third Party Advisory
usn.ubuntu.com / 4321-1
Third Party Advisory
debian.org / security/2020/dsa-4649
Third Party Advisory
haproxy.org / download/2.1/src/CHANGELOG
Release NotesVendor Advisory
mail-archive.com / haproxy%40formilux.org/msg36876.html
haproxy.org
Vendor Advisory