CVE-2026-40210 Out-of-bounds read in SetMacAddrAction
Medium 4.8
Published
Updated
Check this codebase for CVE-2026-40210 and fix it if it is affected.
What it is: CVE-2026-40210 is a medium-severity vulnerability in PowerDNS DNSdist, published on 25 Jun 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-2026-40210 in the wild and no public exploit code.
Affected product: PowerDNS DNSdist. 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-2026-40210/ (Markdown: https://insights.sbomify.com/CVE-2026-40210/index.md)
An out-of-bounds read in PowerDNS DNSdist allows attackers to leak uninitialized memory or cause a crash via SetMacAddrAction.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40210?
CVE-2026-40210 is a medium-severity vulnerability in PowerDNS DNSdist, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An out-of-bounds read might happen when SetMacAddrAction is used, potentially resulting in uninitialized memory being sent over the network or a crash.
Weakness: CWE-126
Which versions are affected by CVE-2026-40210?
How do I fix CVE-2026-40210?
Apply the vendor's patch.
Is CVE-2026-40210 being exploited?
There is no known exploitation of CVE-2026-40210 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-40210, GHSA-5292-qc6p-vf38, UBUNTU-CVE-2026-40210.