# CVE-2026-44690: Cross-zone wildcard cache poisoning via RRSIG.labels manipulation > Attackers can poison DNS cache for sibling domains via RRSIG manipulation in Unbound, requiring aggressive NSEC processing enabled. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 22 Jul 2026 - **Updated:** 22 Jul 2026 - **Also known as:** ALPINE-CVE-2026-44690, ALSA-2026:55784, AZL-92931, DEBIAN-CVE-2026-44690, ECHO-e154-63c5-79fe, GHSA-jwg4-375h-655h, RHSA-2026:55784, RLSA-2026:55784, ROOT-OS-DEBIAN-11-CVE-2026-44690, ROOT-OS-DEBIAN-12-CVE-2026-44690, UBUNTU-CVE-2026-44690 ## What is CVE-2026-44690? CVE-2026-44690 is a high-severity vulnerability in Nlnetlabs Unbound, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### 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. Weakness: CWE-345 (Insufficient Verification of Data Authenticity) ## Which versions are affected by CVE-2026-44690? It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `python3-unbound` | AlmaLinux:8 | All versions | 1.16.2-5.14.el8_10 | | `unbound` | AlmaLinux:8 | All versions | 1.16.2-5.14.el8_10 | | `unbound-devel` | AlmaLinux:8 | All versions | 1.16.2-5.14.el8_10 | | `unbound-libs` | AlmaLinux:8 | All versions | 1.16.2-5.14.el8_10 | | `python3-unbound` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `python3-unbound-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound-libs` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound-libs-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:1.16.2-5.14.el8_10 | | `unbound` | Rocky Linux:8 | All versions | 0:1.16.2-5.14.el8_10 | Products: Nlnetlabs Unbound. ## How do I fix CVE-2026-44690? Upgrade to a fixed version. ## Is CVE-2026-44690 being exploited? There is no known exploitation of CVE-2026-44690 in the wild and no public exploit code. ## Other vulnerabilities in Nlnetlabs Unbound - [CVE-2026-81642](https://insights.sbomify.com/CVE-2026-81642/): Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY (critical 9.1) - [CVE-2026-33278](https://insights.sbomify.com/CVE-2026-33278/): Possible arbitrary code execution during DNSSEC validation (critical 9.1) - [CVE-2026-42944](https://insights.sbomify.com/CVE-2026-42944/): Heap overflow with multiple NSID, COOKIE, PADDING EDNS options (high 8.7) - [CVE-2026-42959](https://insights.sbomify.com/CVE-2026-42959/): Crash during DNSSEC validation of malicious content (high 8.7) - [CVE-2026-82717](https://insights.sbomify.com/CVE-2026-82717/): CNAME synthesis could lead to heap corruption (high 8.4) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-44690 and fix it if it is affected. What it is: CVE-2026-44690 is a high-severity vulnerability in Nlnetlabs Unbound, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-44690 in the wild and no public exploit code. Affected product: Nlnetlabs Unbound. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-44690/ (Markdown: https://insights.sbomify.com/CVE-2026-44690/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44690 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44690 - OSV: https://osv.dev/vulnerability/CVE-2026-44690 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-44690/ Summaries are generated and may contain mistakes; the official description above is the record.