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Vulnerability Intelligence

CVE-2023-50387

High

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue.

Published Feb 14, 2024 · Updated Aug 12, 2026 · Also known as ALPINE-CVE-2023-50387, DEBIAN-CVE-2023-50387, DLA-3736-1, DLA-3816-1, DLA-3859-1, DSA-5620-1, DSA-5626-1, SUSE-SU-2025:0130-1, UBUNTU-CVE-2023-50387, USN-6665-1, USN-6723-1

Key Facts

Patch immediately
  • CVE-2023-50387 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting Bind (Isc), Knot Resolver (Nic), Unbound (Nlnetlabs) and 22 more products.
  • It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
  • EPSS estimates a 100% probability of exploitation in the next 30 days.
  • Fixed versions are available, including Bind 2:9.11.36-11.el8_9.1, Bind 2:9.11.36-14.el8_10, Bind 2:9.16.23-18.el9_4.1.
  • Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v3.1

7.5

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

EPSS (30-day exploit likelihood)

100%

Higher than 99.9% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

None known

Get the full CVE-2023-50387 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

Affected Products

718 affected entries in total
ProductAffected versionsFixed in
BindIscSee advisory9.16.46
Knot ResolverNicSee advisory5.71
UnboundNlnetlabsSee advisory1.19.1
RecursorPowerdnsSee advisory4.8.6
DnsmasqThekelleysSee advisory2.90
20 more affected products in the full CVE brief

Patched Releases

Bind

2:9.11.36-11.el8_9.1, 2:9.11.36-14.el8_10, 2:9.16.23-18.el9_4.1, 32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.36-8.el8_8.4, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.23-11.el9_2.4, 32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.23-18.el9_4.1, 32:9.16.48-1.amzn2023.0.1, 32:9.8.2-0.68.rc1.el6_10.14, 9.11.22-3.52.1, 9.16.48-1, 9.16.48-150400.5.40.1, 9.16.48-150500.8.16.1, 9.16.48-r0, 9.16.6-150000.12.74.2, 9.16.6-150300.22.44.1, 9.18.24-1.1, 9.18.24-r0, 9.20.0-1, <=9.16.46

bind-chroot

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1

bind-chrootenv

9.11.22-3.52.1, 9.16.6-150000.12.74.2, 9.16.6-150300.22.44.1

bind-devel

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1, 9.11.22-3.52.1, 9.16.6-150000.12.74.2, 9.16.6-150300.22.44.1

bind-dlz-filesystem

32:9.16.48-1.amzn2023.0.1

bind-dlz-ldap

32:9.16.48-1.amzn2023.0.1

bind-dlz-mysql

32:9.16.48-1.amzn2023.0.1

bind-dlz-sqlite3

32:9.16.48-1.amzn2023.0.1

bind-dnssec-doc

32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1

bind-dnssec-utils

32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1

bind-doc

32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1, 9.11.22-3.52.1, 9.16.48-150400.5.40.1, 9.16.48-150500.8.16.1, 9.16.6-150000.12.74.2, 9.16.6-150300.22.44.1, 9.18.24-1.1

bind-dyndb-ldap

0:11.1-7.el7_9.1, 0:11.9-8.el9_3.3, 0:2.3-8.el6_10.1, 11.1-7.el7_9.1, 11.9-8.el9_3.3, 11.9-8.el9_3.3.alma.1, 11.9-9.el9_4, 11.9-9.el9_4.alma.1

bind-export-devel

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16

bind-export-libs

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16

bind-libs

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1

bind-libs-lite

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16

bind-license

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.23-14.el9_3.4, 32:9.16.23-18.0.1.el9_4.1, 32:9.16.48-1.amzn2023.0.1

bind-lite-devel

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16

bind-modules-bdbhpt

9.18.24-1.1

bind-modules-generic

9.18.24-1.1

bind-modules-ldap

9.18.24-1.1

bind-modules-mysql

9.18.24-1.1

bind-modules-perl

9.18.24-1.1

bind-modules-sqlite3

9.18.24-1.1

bind-pkcs11

32:9.11.36-11.el8_9.1, 32:9.11.36-14.el8_10, 32:9.11.4-26.P2.amzn2.13.6, 32:9.11.4-26.P2.el7_9.16, 32:9.16.48-1.amzn2023.0.1

Timeline

  1. Publicly disclosed

    Feb 14, 2024

  2. Last updated

    Aug 12, 2026

Weakness Type

  • CWE-400 Uncontrolled Resource Consumption
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

15 more references in the full CVE brief

FAQ

Common Questions.

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