CVE-2026-42534
Jostle logic bypass degrades resolution performance
CVE-2026-42534 is fixed in 15 products on 1 platform, first by libunbound8 1.24.2-1ubuntu2.1, released May 19, 2026. It is not reported as exploited. Patch Radar priority: High.
High
CVSS
7.5
Low
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0060
49th percentile
The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver. Security Fix(es): * unbound: Unbound: Denial of Service via excessive EDNS options (CVE-2026-41292) * unbound: Unbound: Cache manipulation via 'ghost domain names' attack (CVE-2026-40622) * unbound: Unbound: Denial of Service due to excessive resource consumption with large DNS Resource Record Sets (CVE-2026-44390) * unbound: Unbound: Denial of Service due to degraded resolution performance in jostle logic (CVE-2026-42534) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| libunbound8 · Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.15 | libunbound8 1.13.1-1ubuntu5.15 | May 27, 2026 |
| libunbound8 · Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.8 | libunbound8 1.19.2-1ubuntu3.8 | May 27, 2026 |
| libunbound8 · Ubuntu 25.10 (questing) | 1.22.0-2ubuntu2.3 | libunbound8 1.22.0-2ubuntu2.3 | May 27, 2026 |
| libunbound8 · Ubuntu 26.04.1 LTS (resolute) | 1.24.2-1ubuntu2.1 | libunbound8 1.24.2-1ubuntu2.1 | May 19, 2026 |
| python3-unbound · RHEL 8 | 0:1.16.2-5.12.el8_10 | RHSA-2026:37282 | Jul 31, 2026 |
| python3-unbound · RHEL 9 | 0:1.24.2-3.el9_8.2 | RHSA-2026:36777 | Jul 31, 2026 |
| python3-unbound · Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.15 | python3-unbound 1.13.1-1ubuntu5.15 | May 27, 2026 |
| python3-unbound · Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.8 | python3-unbound 1.19.2-1ubuntu3.8 | May 27, 2026 |
| python3-unbound · Ubuntu 25.10 (questing) | 1.22.0-2ubuntu2.3 | python3-unbound 1.22.0-2ubuntu2.3 | May 27, 2026 |
| python3-unbound · Ubuntu 26.04.1 LTS (resolute) | 1.24.2-1ubuntu2.1 | python3-unbound 1.24.2-1ubuntu2.1 | May 19, 2026 |
| python3-unbound · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| python3-unbound · almalinux 8 | 1.16.2-5.12.el8_10 | ALSA-2026:37282 | Jul 9, 2026 |
| python3-unbound · almalinux 9 | 1.24.2-3.el9_8.2 | ALSA-2026:36777 | Jul 8, 2026 |
| python3-unbound · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| python3-unbound · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| python3-unbound · ol 8 | 0:1.16.2-5.12.el8_10 | ELSA-2026-37282 | Jul 9, 2026 |
| python3-unbound · ol 9 | 0:1.24.2-3.el9_8.2 | ELSA-2026-36777 | Jul 9, 2026 |
| python3-unbound-debuginfo · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound · Debian 13.5 (trixie) | 1.22.0-2+deb13u3 | DEBIAN-CVE-2026-42534 | May 27, 2026 |
| unbound · Debian 14 | 1.25.1-1 | DEBIAN-CVE-2026-42534 | May 27, 2026 |
| unbound · RHEL 10 | 1.24.2-7.el10_2.2 | RHSA-2026:36320 | May 20, 2026 |
| unbound · RHEL 8 | 0:1.16.2-5.12.el8_10 | RHSA-2026:37282 | Jul 31, 2026 |
| unbound · RHEL 9 | 0:1.24.2-3.el9_8.2 | RHSA-2026:36777 | Jul 31, 2026 |
| unbound · Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.15 | unbound 1.13.1-1ubuntu5.15 | May 27, 2026 |
| unbound · Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.8 | unbound 1.19.2-1ubuntu3.8 | May 27, 2026 |
| unbound · Ubuntu 25.10 (questing) | 1.22.0-2ubuntu2.3 | unbound 1.22.0-2ubuntu2.3 | May 27, 2026 |
| unbound · Ubuntu 26.04.1 LTS (resolute) | 1.24.2-1ubuntu2.1 | unbound 1.24.2-1ubuntu2.1 | May 19, 2026 |
| unbound · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound · almalinux 8 | 1.16.2-5.12.el8_10 | ALSA-2026:37282 | Jul 9, 2026 |
| unbound · almalinux 9 | 1.24.2-3.el9_8.2 | ALSA-2026:36777 | Jul 8, 2026 |
| unbound · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound · ol 8 | 0:1.16.2-5.12.el8_10 | ELSA-2026-37282 | Jul 9, 2026 |
| unbound · ol 9 | 0:1.24.2-3.el9_8.2 | ELSA-2026-36777 | Jul 9, 2026 |
| unbound · opensuse-leap 16.0 | 1.24.1-160000.2.1 | OPENSUSE-SU-2026:21083-1 | Jun 18, 2026 |
| unbound · rocky 10 | 0:1.24.2-7.el10_2.2 | RLSA-2026:36320 | Jul 28, 2026 |
| unbound · rocky 8 | 0:1.16.2-5.12.el8_10 | RLSA-2026:37282 | Jul 28, 2026 |
| unbound · rocky 9 | 0:1.24.2-3.el9_8.2 | RLSA-2026:36777 | Jul 28, 2026 |
| unbound · sles 16.0 | 1.24.1-160000.2.1 | SUSE-SU-2026:22160-1 | Jun 18, 2026 |
| unbound-anchor · Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.15 | unbound-anchor 1.13.1-1ubuntu5.15 | May 27, 2026 |
| unbound-anchor · Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.8 | unbound-anchor 1.19.2-1ubuntu3.8 | May 27, 2026 |
| unbound-anchor · Ubuntu 25.10 (questing) | 1.22.0-2ubuntu2.3 | unbound-anchor 1.22.0-2ubuntu2.3 | May 27, 2026 |
| unbound-anchor · Ubuntu 26.04.1 LTS (resolute) | 1.24.2-1ubuntu2.1 | unbound-anchor 1.24.2-1ubuntu2.1 | May 19, 2026 |
| unbound-anchor · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound-anchor · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-anchor · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound-anchor-debuginfo · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-debuginfo · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-debugsource · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-devel · RHEL 8 | 0:1.16.2-5.12.el8_10 | RHSA-2026:37282 | Jul 31, 2026 |
| unbound-devel · RHEL 9 | 0:1.24.2-3.el9_8.2 | RHSA-2026:36777 | Jul 31, 2026 |
| unbound-devel · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound-devel · almalinux 8 | 1.16.2-5.12.el8_10 | ALSA-2026:37282 | Jul 9, 2026 |
| unbound-devel · almalinux 9 | 1.24.2-3.el9_8.2 | ALSA-2026:36777 | Jul 8, 2026 |
| unbound-devel · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-devel · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound-devel · ol 8 | 0:1.16.2-5.12.el8_10 | ELSA-2026-37282 | Jul 9, 2026 |
| unbound-devel · ol 9 | 0:1.24.2-3.el9_8.2 | ELSA-2026-36777 | Jul 9, 2026 |
| unbound-dracut · RHEL 9 | 0:1.24.2-3.el9_8.2 | RHSA-2026:36777 | Jul 31, 2026 |
| unbound-dracut · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound-dracut · almalinux 9 | 1.24.2-3.el9_8.2 | ALSA-2026:36777 | Jul 8, 2026 |
| unbound-dracut · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound-dracut · ol 9 | 0:1.24.2-3.el9_8.2 | ELSA-2026-36777 | Jul 9, 2026 |
| unbound-host · Ubuntu 22.04.1 LTS (jammy) | 1.13.1-1ubuntu5.15 | unbound-host 1.13.1-1ubuntu5.15 | May 27, 2026 |
| unbound-host · Ubuntu 24.04.5 LTS (noble) | 1.19.2-1ubuntu3.8 | unbound-host 1.19.2-1ubuntu3.8 | May 27, 2026 |
| unbound-host · Ubuntu 25.10 (questing) | 1.22.0-2ubuntu2.3 | unbound-host 1.22.0-2ubuntu2.3 | May 27, 2026 |
| unbound-host · Ubuntu 26.04.1 LTS (resolute) | 1.24.2-1ubuntu2.1 | unbound-host 1.24.2-1ubuntu2.1 | May 19, 2026 |
| unbound-libs · RHEL 8 | 0:1.16.2-5.12.el8_10 | RHSA-2026:37282 | Jul 31, 2026 |
| unbound-libs · RHEL 9 | 0:1.24.2-3.el9_8.2 | RHSA-2026:36777 | Jul 31, 2026 |
| unbound-libs · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound-libs · almalinux 8 | 1.16.2-5.12.el8_10 | ALSA-2026:37282 | Jul 9, 2026 |
| unbound-libs · almalinux 9 | 1.24.2-3.el9_8.2 | ALSA-2026:36777 | Jul 8, 2026 |
| unbound-libs · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-libs · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound-libs · ol 8 | 0:1.16.2-5.12.el8_10 | ELSA-2026-37282 | Jul 9, 2026 |
| unbound-libs · ol 9 | 0:1.24.2-3.el9_8.2 | ELSA-2026-36777 | Jul 9, 2026 |
| unbound-libs-debuginfo · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-utils · almalinux 10 | 1.24.2-7.el10_2.2 | ALSA-2026:36320 | Jul 7, 2026 |
| unbound-utils · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
| unbound-utils · ol 10 | 0:1.24.2-7.el10_2.2 | ELSA-2026-36320 | Jul 16, 2026 |
| unbound-utils-debuginfo · amzn 2023 | 1.17.1-1.amzn2023.0.12 | ALAS2023-2026-1756 | May 25, 2026 |
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