Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NLnet Labs | Unbound | < 1.26.1 | 1.26.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | unbound | 1.26.1-1 | — |
| Debian 13 | unbound | 1.26.1-0+deb13u1 | — |
| Debian 12 | unbound | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | unbound | No fix yet | — |
| Ubuntu 26.04 LTS | unbound | 1.24.2-1ubuntu2.3 | USN-8873-1 |
| Ubuntu 24.04 LTS | unbound | 1.19.2-1ubuntu3.10 | USN-8873-1 |
| Ubuntu 22.04 LTS | unbound | 1.13.1-1ubuntu5.16 | USN-8873-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | unbound | 1.9.4-2ubuntu1.11+esm2 | USN-8873-1 |
| Ubuntu Pro 18.04 LTS | unbound | 1.6.7-1ubuntu2.6+esm5 | USN-8873-1 |
| Ubuntu Pro 16.04 LTS | unbound | 1.5.8-1ubuntu1.1+esm4 | USN-8873-1 |
| Ubuntu Pro 14.04 LTS | unbound | 1.4.22-1ubuntu4.14.04.3+esm4 | USN-8873-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | unbound +6 | 1.24.2-7.el10_2.6 | RHSA-2026:71419 |
| RHEL 9 | unbound +4 | 1.24.2-3.el9_8.8 | RHSA-2026:71487 |
| RHEL 8 | unbound +3 | 1.16.2-5.14.el8_10.4 | RHSA-2026:70754 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | unbound +1 | 1.20.0-18.el10_0.13 | RHSA-2026:71459 |
| RHEL 9.6 EUS | unbound +1 | 1.16.2-19.el9_6.2 | RHSA-2026:71460 |
| RHEL 9.4 E4S | unbound +2 | 1.16.2-8.el9_4.3 | RHSA-2026:71611 |
| RHEL 9.2 E4S | unbound +2 | 1.16.2-3.el9_2.6 | RHSA-2026:71610 |
| RHEL 8.8 TUS | unbound +3 | 1.16.2-5.el8_8.6 | RHSA-2026:72264 |
| RHEL 8.8 E4S | unbound +3 | 1.16.2-5.el8_8.6 | RHSA-2026:72264 |
| RHEL 8.6 EUS Long Life | unbound +1 | 1.7.3-17.el8_6.8 | RHSA-2026:72110 |
| RHEL 8.6 AUS | unbound +1 | 1.7.3-17.el8_6.8 | RHSA-2026:72110 |
| RHEL 8.4 EUS Long Life | unbound +1 | 1.7.3-15.el8_4.4 | RHSA-2026:72183 |
| RHEL 8.4 AUS | unbound +1 | 1.7.3-15.el8_4.4 | RHSA-2026:72183 |
| RHEL 7 ELS | unbound +3 | 1.6.6-5.el7_9.2 | RHSA-2026:72199 |
| Red Hat Hardened Images 1 | unbound +7 | 1.26.1-1.hum1 | RHSA-2026:68590 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | unbound +6 | 1.24.2-7.el10_2.6 | ALSA-2026:71419 |
| AlmaLinux 9 | unbound +4 | 1.24.2-3.el9_8.8 | ALSA-2026:71487 |
| AlmaLinux 8 | unbound +3 | 1.16.2-5.14.el8_10.4 | ALSA-2026:70754 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | unbound | 1.24.2-7.el10_2.6 | RLSA-2026:71419 |
| Rocky Linux 9 | unbound | 1.24.2-3.el9_8.8 | RLSA-2026:71487 |
| Rocky Linux 8 | unbound | 1.16.2-5.14.el8_10.4 | RLSA-2026:70754 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | unbound | 1.26.1-150600.23.24.1 | SUSE-SU-2026:4620-1 |
| SLES 15 SP6 | unbound | 1.26.1-150600.23.24.1 | SUSE-SU-2026:4620-1 |
| SLES 15 SP5 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
| SLES 15 SP4 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
Show 11 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | unbound | 1.26.1-160000.1.1 | SUSE-SU-2026:24226-1 |
| SLES for SAP 15 SP6 | unbound | 1.26.1-150600.23.24.1 | SUSE-SU-2026:4620-1 |
| SLES for SAP 15 SP5 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
| SLES for SAP 15 SP4 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
| SLES 16.0 | unbound | 1.26.1-160000.1.1 | SUSE-SU-2026:24226-1 |
| SLE Micro 6.2 | unbound | 1.26.1-160000.1.1 | SUSE-SU-2026:24128-1 |
| SLE Micro 6.1 | unbound | 1.26.1-slfo.1.1_1.1 | SUSE-SU-2026:24376-1 |
| SLE Micro 6.0 | unbound | 1.26.1-159998.1.1 | SUSE-SU-2026:24135-1 |
| SLE Micro 5.5 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
| SLE HPC 15 SP5 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
| SLE HPC 15 SP4 | unbound | 1.26.1-150100.10.31.1 | SUSE-SU-2026:4624-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | unbound | 1.26.1-1.1 | openSUSE-SU-2026:11930-1 |
| openSUSE Leap 16.0 | unbound | 1.26.1-160000.1.1 | openSUSE-SU-2026:22082-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | unbound | 1.25.2-r2 | — |
| Alpine v3.23 | unbound | 1.25.2-r0 | — |
| Alpine v3.22 | unbound | 1.25.2-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | unbound +5 | 1.17.1-1.amzn2023.0.14 | ALAS2023-2026-3101 |
| Amazon Linux 2 | unbound +4 | 1.7.3-15.amzn2.0.16 | ALAS2-2026-3928 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | unbound | 1.26.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | unbound +6 | 1.24.2-7.el10_2.6 | ELSA-2026-71419 |
| Oracle Linux 9 | unbound +4 | 1.24.2-3.el9_8.8 | ELSA-2026-71487 |
| Oracle Linux 8 | unbound +3 | 1.16.2-5.14.el8_10.4 | ELSA-2026-70754 |
| Oracle Linux 7 | unbound +3 | 1.6.6-5.0.3.el7_8 | ELSA-2026-72199 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
suominen/CVE-2026-81642 ★ 0 · Sep 18, 2026
Tracking the Unbound CVE-2026-81642 DNSKEY digest heap overflow
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 34
- WID-SEC-2026-3392 Unbound: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
- ALSA-2026:71487 Critical: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:71419 Critical: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:70754 Critical: unbound security update AlmaLinux Security Advisories · Oct 29, 2026
- SUSE-SU-2026:24376-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 27, 2026
- ELSA-2026-72199 Critical: unbound security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Oct 23, 2026
- SUSE-SU-2026:24226-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 21, 2026
- openSUSE-SU-2026:22082-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 19, 2026
- RHSA-2026:71487 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:71419 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:70754 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 19, 2026
- RHSA-2026:72264 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:72199 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:72183 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:72110 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:71611 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:71610 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:71460 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:71459 Red Hat Security Advisory: unbound security update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:68590 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- SUSE-SU-2026:24135-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 15, 2026
- SUSE-SU-2026:24128-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 13, 2026
- SUSE-SU-2026:4620-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 13, 2026
- SUSE-SU-2026:4624-1 Security update for unbound SUSE / openSUSE Security Updates · Oct 13, 2026
- USN-8873-1 unbound vulnerabilities Ubuntu Security Notices (USN) · Oct 6, 2026
- openSUSE-SU-2026:11930-1 libunbound8-1.26.1-1.1 on GA media SUSE / openSUSE Security Updates · Sep 30, 2026
- RLSA-2026:71487 Critical: unbound security update Rocky Linux Security Advisories · Sep 25, 2026
- RLSA-2026:71419 Critical: unbound security update Rocky Linux Security Advisories · Sep 25, 2026
- RLSA-2026:70754 Critical: unbound security update Rocky Linux Security Advisories · Sep 24, 2026
- ELSA-2026-71487 Critical: unbound security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Sep 24, 2026
- ELSA-2026-70754 Critical: unbound security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Sep 24, 2026
- ELSA-2026-71419 Critical: unbound security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Sep 24, 2026
- ALAS2023-2026-3101 Critical: unbound security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 17, 2026
- ALAS2-2026-3928 Critical: unbound security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 17, 2026
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-81642.txt vendor-advisory