Vulnerability · Published Jul 22, 2026 · Assigned by NLnet Labs
CVE-2026-44690Cross-zone wildcard cache poisoning via RRSIG.labels manipulation
High 7.5
In plain English
A high-severity insufficient verification of data authenticity in Unbound from NLnet Labs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | python3-unbound | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:8 | python3-unbound | 1.16.2-5.14.el8_10 | ALSA-2026:55784 |
| AlmaLinux:9 | python3-unbound | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux:10 | unbound | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:8 | unbound | 1.16.2-5.14.el8_10 | ALSA-2026:55784 |
| AlmaLinux:9 | unbound | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux:10 | unbound-anchor | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:10 | unbound-devel | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:8 | unbound-devel | 1.16.2-5.14.el8_10 | ALSA-2026:55784 |
| AlmaLinux:9 | unbound-devel | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux:10 | unbound-dracut | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:9 | unbound-dracut | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux:10 | unbound-libs | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| AlmaLinux:8 | unbound-libs | 1.16.2-5.14.el8_10 | ALSA-2026:55784 |
| AlmaLinux:9 | unbound-libs | 1.24.2-3.el9_8.4 | ALSA-2026:55841 |
| AlmaLinux:10 | unbound-utils | 1.24.2-7.el10_2.4 | ALSA-2026:55892 |
| Alpine:v3.22 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-44690 |
| Alpine:v3.23 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-44690 |
| Alpine:v3.24 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-44690 |
| Debian:12 | unbound | no fix listed | DEBIAN-CVE-2026-44690 |
| Debian:13 | unbound | 1.26.1-0+deb13u1 | DEBIAN-CVE-2026-44690 |
| Debian:14 | unbound | 1.25.2-1 | DEBIAN-CVE-2026-44690 |
| Rocky Linux:10 | unbound | 0:1.24.2-7.el10_2.4 | RLSA-2026:55892 |
| Rocky Linux:8 | unbound | 0:1.16.2-5.14.el8_10 | RLSA-2026:55784 |
| Rocky Linux:9 | unbound | 0:1.24.2-3.el9_8.4 | RLSA-2026:55841 |
| Ubuntu:22.04:LTS | unbound | 1.13.1-1ubuntu5.17 | USN-8946-1 |
| Ubuntu:22.04:LTS | unbound | 1.13.1-1ubuntu5.17 | UBUNTU-CVE-2026-44690 |
| Ubuntu:24.04:LTS | unbound | 1.19.2-1ubuntu3.12 | UBUNTU-CVE-2026-44690 |
| Ubuntu:24.04:LTS | unbound | 1.19.2-1ubuntu3.12 | USN-8946-1 |
| Ubuntu:26.04:LTS | unbound | 1.24.2-1ubuntu2.4 | UBUNTU-CVE-2026-44690 |
| Ubuntu:26.04:LTS | unbound | 1.24.2-1ubuntu2.4 | USN-8946-1 |
| Ubuntu:26.10 | unbound | no fix listed | UBUNTU-CVE-2026-44690 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NLnet Labs | Unbound | 1.7.0 – before 1.25.2 |
Weakness: CWE-345 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44690.txt vendor-advisory