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Fencer Intel
high 7.5

CVE-2018-20102 json

An out-of-bounds read in dns_validate_dns_response in dns.c was discovered in HAProxy through 1.8.14.

published 2018-12-12 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-12672

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.2%
EPSS 4.2% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

An out-of-bounds read in dns_validate_dns_response in dns.c was discovered in HAProxy through 1.8.14. Due to a missing check when validating DNS responses, remote attackers might be able read the 16 bytes corresponding to an AAAA record from the non-initialized part of the buffer, possibly accessing anything that was left on the stack, or even past the end of the 8193-byte buffer, depending on the value of accepted_payload_size.

Patch / fix

  • haproxy Debian 14, Debian 13, Debian 12 1.8.15-1

debian advisories DEBIAN-CVE-2018-20102

  • haproxy Ubuntu 16.04 LTS 1.6.3-1ubuntu0.2
  • haproxy Ubuntu 18.04 LTS 1.8.8-1ubuntu0.3

ubuntu advisories UBUNTU-CVE-2018-20102

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 3.11, openshift 3.9 1.8.17-3.el7
  • jenkins openshift 3.11 2.150.2.1549032159-1.el7
  • haproxy18 openshift 3.11, openshift 3.9 1.8.17-3.el7
  • prometheus openshift 3.11 3.11.82-1.git.5027.9d24833.el7
  • atomic-openshift openshift 3.11 3.11.82-1.git.0.08bc31b.el7
  • jenkins-2-plugins openshift 3.11 3.11.1549642489-1.el7
  • openshift-ansible openshift 3.11 3.11.82-3.git.0.9718d0a.el7
  • atomic-openshift-pod openshift 3.11 3.11.82-1.git.0.08bc31b.el7

red hat advisories RHBA-2019:0326RHSA-2019:1436RHSA-2019:0547

  • haproxy SLE High Availability Extension 15 1.8.15~git0.6b6a350a-3.6.2

suse advisories SUSE-SU-2019:0061-1

  • haproxy Arch Linux 1.9.0-1

arch linux advisories AVG-836

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-2018-20102 updated cvss 6.5

haproxy: Out-of-bounds read in dns.c:dns_validate_dns_response() allows for memory disclosure

  • Red Hat OpenShift Container Platform 3.7 haproxy18
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 3.10 haproxy, haproxy18
    affected: no fix available
  • Red Hat OpenShift Container Platform 3.9 haproxy 1.8.17-3.el7, haproxy18 1.8.17-3.el7
    fixed: vendor fix RHSA-2019:0547
  • Red Hat OpenShift Container Platform 3.11 haproxy 1.8.17-3.el7, haproxy18 1.8.17-3.el7, jenkins 2.150.2.1549032159-1.el7, jenkins-2-plugins 3.11.1549642489-1.el7, prometheus 3.11.82-1.git.5027.9d24833.el7, atomic-openshift 3.11.82-1.git.0.08bc31b.el7, +33 more
    fixed: vendor fix RHBA-2019:0326
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-haproxy18-haproxy 1.8.17-1.el7, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.4) rh-haproxy18-haproxy 1.8.17-1.el7, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) rh-haproxy18-haproxy 1.8.17-1.el7, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) rh-haproxy18-haproxy 1.8.17-1.el7, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-haproxy18-haproxy 1.8.17-1.el7, rh-haproxy18-haproxy-syspaths 1.8.17-1.el7
    fixed: vendor fix RHSA-2019:1436
  • Red Hat Enterprise Linux 6 haproxy Red Hat Enterprise Linux 7 haproxy Red Hat Enterprise Linux 8 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

4.15% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness

References

Sources

Fencer Intel 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.