CVE-2026-81642

Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

CVE-2026-81642 is fixed in 17 products on 1 platform, first by libunbound8 1.24.2-1ubuntu2.3, released September 16, 2026. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
9.8
Important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0096
61st percentile

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.

Where it's fixed

ProductFixed inFixReleased
Linux
libunbound2 · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 libunbound2 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
libunbound8 · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 libunbound8 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
libunbound8 · Ubuntu 22.04.1 LTS (jammy) 1.13.1-1ubuntu5.16 libunbound8 1.13.1-1ubuntu5.16 Oct 6, 2026
libunbound8 · Ubuntu 24.04.5 LTS (noble) 1.19.2-1ubuntu3.10 libunbound8 1.19.2-1ubuntu3.10 Oct 6, 2026
libunbound8 · Ubuntu 26.04.1 LTS (resolute) 1.24.2-1ubuntu2.3 libunbound8 1.24.2-1ubuntu2.3 Sep 16, 2026
python-unbound · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 python-unbound 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
python-unbound · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 python-unbound 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
python3-unbound · RHEL 8 0:1.16.2-5.14.el8_10.4 RHSA-2026:70754 Sep 23, 2026
python3-unbound · RHEL 9 0:1.24.2-3.el9_8.8 RHSA-2026:71487 Sep 24, 2026
python3-unbound · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 python3-unbound 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
python3-unbound · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 python3-unbound 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
python3-unbound · Ubuntu 22.04.1 LTS (jammy) 1.13.1-1ubuntu5.16 python3-unbound 1.13.1-1ubuntu5.16 Oct 6, 2026
python3-unbound · Ubuntu 24.04.5 LTS (noble) 1.19.2-1ubuntu3.10 python3-unbound 1.19.2-1ubuntu3.10 Oct 6, 2026
python3-unbound · Ubuntu 26.04.1 LTS (resolute) 1.24.2-1ubuntu2.3 python3-unbound 1.24.2-1ubuntu2.3 Sep 16, 2026
python3-unbound · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
python3-unbound · almalinux 8 1.16.2-5.14.el8_10.4 ALSA-2026:70754 Sep 23, 2026
python3-unbound · almalinux 9 1.24.2-3.el9_8.8 ALSA-2026:71487 Sep 24, 2026
python3-unbound · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
python3-unbound · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
python3-unbound · ol 8 0:1.16.2-5.14.el8_10.4 ELSA-2026-70754 Sep 24, 2026
python3-unbound · ol 9 0:1.24.2-3.el9_8.8 ELSA-2026-71487 Sep 24, 2026
python3-unbound-debuginfo · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound · Debian 13.5 (trixie) 1.26.1-0+deb13u1 DEBIAN-CVE-2026-81642 Sep 19, 2026
unbound · Debian 14 1.26.1-1 DEBIAN-CVE-2026-81642 Sep 19, 2026
unbound · RHEL 10 1.20.0-18.el10_0.13 RHSA-2026:71459 Sep 24, 2026
unbound · RHEL 8 0:1.16.2-5.14.el8_10.4 RHSA-2026:70754 Sep 23, 2026
unbound · RHEL 9 0:1.24.2-3.el9_8.8 RHSA-2026:71487 Sep 24, 2026
unbound · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 unbound 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
unbound · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 unbound 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
unbound · Ubuntu 22.04.1 LTS (jammy) 1.13.1-1ubuntu5.16 unbound 1.13.1-1ubuntu5.16 Oct 6, 2026
unbound · Ubuntu 24.04.5 LTS (noble) 1.19.2-1ubuntu3.10 unbound 1.19.2-1ubuntu3.10 Oct 6, 2026
unbound · Ubuntu 26.04.1 LTS (resolute) 1.24.2-1ubuntu2.3 unbound 1.24.2-1ubuntu2.3 Sep 16, 2026
unbound · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound · almalinux 8 1.16.2-5.14.el8_10.4 ALSA-2026:70754 Sep 23, 2026
unbound · almalinux 9 1.24.2-3.el9_8.8 ALSA-2026:71487 Sep 24, 2026
unbound · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound · ol 8 0:1.16.2-5.14.el8_10.4 ELSA-2026-70754 Sep 24, 2026
unbound · ol 9 0:1.24.2-3.el9_8.8 ELSA-2026-71487 Sep 24, 2026
unbound · opensuse-leap 16.0 1.26.1-160000.1.1 OPENSUSE-SU-2026:22082-1 Nov 7, 2026
unbound · rocky 10 0:1.24.2-7.el10_2.6 RLSA-2026:71419 Sep 25, 2026
unbound · rocky 8 0:1.16.2-5.14.el8_10.4 RLSA-2026:70754 Sep 24, 2026
unbound · rocky 9 0:1.24.2-3.el9_8.8 RLSA-2026:71487 Sep 25, 2026
unbound · sles 15.6 1.26.1-150600.23.24.1 SUSE-SU-2026:4620-1 Nov 7, 2026
unbound · sles 15.7 1.26.1-150600.23.24.1 SUSE-SU-2026:4620-1 Nov 7, 2026
unbound · sles 16.0 1.26.1-160000.1.1 SUSE-SU-2026:24226-1 Nov 7, 2026
unbound-anchor · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 unbound-anchor 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
unbound-anchor · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 unbound-anchor 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
unbound-anchor · Ubuntu 22.04.1 LTS (jammy) 1.13.1-1ubuntu5.16 unbound-anchor 1.13.1-1ubuntu5.16 Oct 6, 2026
unbound-anchor · Ubuntu 24.04.5 LTS (noble) 1.19.2-1ubuntu3.10 unbound-anchor 1.19.2-1ubuntu3.10 Oct 6, 2026
unbound-anchor · Ubuntu 26.04.1 LTS (resolute) 1.24.2-1ubuntu2.3 unbound-anchor 1.24.2-1ubuntu2.3 Sep 16, 2026
unbound-anchor · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound-anchor · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-anchor · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound-anchor-debuginfo · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-debuginfo · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-debugsource · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-devel · RHEL 8 0:1.16.2-5.14.el8_10.4 RHSA-2026:70754 Sep 23, 2026
unbound-devel · RHEL 9 0:1.24.2-3.el9_8.8 RHSA-2026:71487 Sep 24, 2026
unbound-devel · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound-devel · almalinux 8 1.16.2-5.14.el8_10.4 ALSA-2026:70754 Sep 23, 2026
unbound-devel · almalinux 9 1.24.2-3.el9_8.8 ALSA-2026:71487 Sep 24, 2026
unbound-devel · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-devel · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound-devel · ol 8 0:1.16.2-5.14.el8_10.4 ELSA-2026-70754 Sep 24, 2026
unbound-devel · ol 9 0:1.24.2-3.el9_8.8 ELSA-2026-71487 Sep 24, 2026
unbound-dracut · RHEL 9 0:1.24.2-3.el9_8.8 RHSA-2026:71487 Sep 24, 2026
unbound-dracut · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound-dracut · almalinux 9 1.24.2-3.el9_8.8 ALSA-2026:71487 Sep 24, 2026
unbound-dracut · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound-dracut · ol 9 0:1.24.2-3.el9_8.8 ELSA-2026-71487 Sep 24, 2026
unbound-host · Ubuntu 18.04.6 LTS (bionic) 1.6.7-1ubuntu2.6+esm5 unbound-host 1.6.7-1ubuntu2.6+esm5 Oct 6, 2026
unbound-host · Ubuntu 20.04 LTS (focal) 1.9.4-2ubuntu1.11+esm2 unbound-host 1.9.4-2ubuntu1.11+esm2 Oct 6, 2026
unbound-host · Ubuntu 22.04.1 LTS (jammy) 1.13.1-1ubuntu5.16 unbound-host 1.13.1-1ubuntu5.16 Oct 6, 2026
unbound-host · Ubuntu 24.04.5 LTS (noble) 1.19.2-1ubuntu3.10 unbound-host 1.19.2-1ubuntu3.10 Oct 6, 2026
unbound-host · Ubuntu 26.04.1 LTS (resolute) 1.24.2-1ubuntu2.3 unbound-host 1.24.2-1ubuntu2.3 Sep 16, 2026
unbound-libs · RHEL 8 0:1.16.2-5.14.el8_10.4 RHSA-2026:70754 Sep 23, 2026
unbound-libs · RHEL 9 0:1.24.2-3.el9_8.8 RHSA-2026:71487 Sep 24, 2026
unbound-libs · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound-libs · almalinux 8 1.16.2-5.14.el8_10.4 ALSA-2026:70754 Sep 23, 2026
unbound-libs · almalinux 9 1.24.2-3.el9_8.8 ALSA-2026:71487 Sep 24, 2026
unbound-libs · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-libs · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound-libs · ol 8 0:1.16.2-5.14.el8_10.4 ELSA-2026-70754 Sep 24, 2026
unbound-libs · ol 9 0:1.24.2-3.el9_8.8 ELSA-2026-71487 Sep 24, 2026
unbound-libs-debuginfo · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-utils · almalinux 10 1.24.2-7.el10_2.6 ALSA-2026:71419 Sep 24, 2026
unbound-utils · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026
unbound-utils · ol 10 0:1.24.2-7.el10_2.6 ELSA-2026-71419 Sep 24, 2026
unbound-utils-debuginfo · amzn 2023 1.17.1-1.amzn2023.0.14 ALAS2023-2026-3101 Sep 17, 2026

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