How to Fix CVE-2026-33599: DNSdist (Bundle Sibling)
By Sai Kiran Pandrala
Last verified: 2026-05-25
CVE-2026-33599 is a sibling vulnerability in the same vendor advisory as CVE-2026-33254. Applying the patched build named in the primary write-up closes this CVE as well.
| Severity | CVSS 3.1 - Low |
|---|---|
| Actively exploited? | Not currently in CISA KEV |
| Affected | Same as the bundle - see CVE-2026-33254 |
| Fixed in | Same patched build as CVE-2026-33254 (See vendor advisory) |
| Type (CWE) | Out-of-bounds Read |
What's different about CVE-2026-33599?
A rogue backend can send a crafted SVCB response to a Discovery of Designated Resolvers request, when requested via either the autoUpgrade (Lua) option to newServer or auto_upgrade (YAML) settings. DDR upgrade is not enabled by default.
The technical impact and remediation are identical to the primary CVE in the bundle. The same vendor patch closes both.
How to fix CVE-2026-33599
Apply the patched build per the primary write-up: How to Fix CVE-2026-33254.
The patch installation procedure, verification commands, and interim mitigations are documented there. Reusing one runbook keeps the rollout consistent across the bundle.
Frequently asked questions
Is CVE-2026-33599 fixed by the same patch as CVE-2026-33254?
Yes. CVE-2026-33599 ships in the same vendor advisory as CVE-2026-33254. Applying the patched build named in the primary write-up closes both.
What is the CVSS score for CVE-2026-33599?
The CVSS base score is 3.1 (Low).
Is it being exploited?
It is not currently listed in CISA KEV.
References
- Official vendor advisory: https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-33599
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary write-up: How to Fix CVE-2026-33254
*Part of the DNSdist bundle. Full procedure at CVE-2026-33254.*