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Fencer Vulns
high 8.8

CVE-2020-11100 in the critical feed json

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 byte…

published 2020-04-02 6 y ago modified 2026-09-08 2 mo ago also BIT-haproxy-2020-11100 , EUVD-2020-3458

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
61.6%
EPSS 61.6% chance of exploitation in 30 days, percentile 99.1%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami haproxy 2.1.4
  • haproxy haproxy 2.1.4
  • haproxy Debian 14, Debian 13, Debian 12 2.0.13-2

debian advisories DEBIAN-CVE-2020-11100

  • haproxy Ubuntu 18.04 LTS 1.8.8-1ubuntu0.10

ubuntu advisories UBUNTU-CVE-2020-11100

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • haproxy openshift 4.4 2.0.13-3.el7
  • haproxy openshift 4.4 2.0.13-3.el8
  • haproxy20 openshift 4.4 2.0.13-3.el7
  • haproxy20 openshift 4.4 2.0.13-3.el8
  • haproxy openshift 3.11 1.8.23-3.el7
  • haproxy18 openshift 3.11 1.8.23-3.el7
  • rh-haproxy18-haproxy RHEL 3 SOFTWARE_COLLECTIONS 1.8.17-1.el7.1
  • rh-haproxy18-haproxy-syspaths RHEL 3 SOFTWARE_COLLECTIONS 1.8.17-1.el7.1

red hat advisories RHSA-2020:1936RHSA-2020:1287RHSA-2020:1289RHSA-2020:1290RHSA-2020:1288

  • haproxy SLE High Availability Extension 15 2.0.10+git0.ac198b92-3.19.1
  • haproxy SLE High Availability Extension 15 SP1 2.0.10+git0.ac198b92-8.12.1

suse advisories SUSE-SU-2020:0852-1SUSE-SU-2020:0851-1

  • haproxy openSUSE Tumbleweed 2.4.4+git0.acb1d0bea-1.2
  • haproxy openSUSE Leap 15.1 2.0.10+git0.ac198b92-lp151.2.9.1

opensuse advisories openSUSE-SU-2024:10839-1openSUSE-SU-2020:0444-1

  • haproxy Alpine 3.11, Alpine 3.10 2.0.14-r0
  • haproxy Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.1.4-r0
  • haproxy Alpine 3.9 1.8.25-r0

alpine advisories ALPINE-CVE-2020-11100

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • haproxy Arch Linux 2.1.4-1

arch linux advisories AVG-1124

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-11100 updated cvss 8.8

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

  • Red Hat Enterprise Linux AppStream (v. 8) haproxy 1.8.15-6.el8_1.1
    fixed: vendor fix RHSA-2020:1288
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) haproxy 1.8.15-5.el8_0.1
    fixed: vendor fix RHSA-2020:1289
  • Red Hat OpenShift Container Platform 3.11 haproxy 1.8.23-3.el7, haproxy18 1.8.23-3.el7
    fixed: vendor fix RHSA-2020:1287
  • Red Hat OpenShift Container Platform 4.4 haproxy 2.0.13-3.el7, haproxy 2.0.13-3.el8, haproxy20 2.0.13-3.el7, haproxy20 2.0.13-3.el8
    fixed: vendor fix RHSA-2020:1936
  • Red Hat OpenShift Container Platform 4.5 openshift4/ose-cli v4.5.0-202007012112.p0, openshift4/ose-pod v4.5.0-202007012112.p0, openshift4/ose-etcd v4.5.0-202007012112.p0, openshift4/ose-tests v4.5.0-202007100518.p0, openshift4/ose-coredns v4.5.0-202007012112.p0, openshift4/ose-grafana v4.5.0-202007012112.p0, +71 more
    fixed: vendor fix RHBA-2020:2409
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-haproxy18-haproxy 1.8.17-1.el7.1, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7.1 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) rh-haproxy18-haproxy 1.8.17-1.el7.1, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7.1 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) rh-haproxy18-haproxy 1.8.17-1.el7.1, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7.1 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-haproxy18-haproxy 1.8.17-1.el7.1, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7.1 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-haproxy18-haproxy 1.8.17-1.el7.1, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7.1
    fixed: vendor fix RHSA-2020:1290
  • Red Hat Enterprise Linux 6 haproxy Red Hat Enterprise Linux 7 haproxy
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

61.59% chance of exploitation in the next 30 days, higher than 99.1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
OSV 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
bitnami haproxy
>=1.8.0, <2.1.4
2.1.4

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.