CVE-2026-33599 Details
Description
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.
An out-of-bounds read vulnerability has been identified in PowerDNS DNSdist versions through 2.0.3 and 1.9.12. This issue arises when a rogue backend sends a crafted SVCB response to a Discovery of Designated Resolvers request, specifically when the autoUpgrade option in Lua or the auto_upgrade setting in YAML is enabled. The vulnerability can lead to a denial-of-service condition, as the crafted response causes memory allocation issues that can be exploited to disrupt normal service operation.
Users can upgrade to PowerDNS DNSdist versions 1.9.13 or 2.0.4, where this vulnerability has been patched. Alternatively, the Discovery of Designated Resolvers feature can be disabled.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 22, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-125 | Out-of-bounds Read | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| powerdns dnsdist | >= 1.9.0, < 1.9.13 >= 2.0.0, < 2.0.4 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 24, 2026 | Initial Analysis | [email protected] |
| Apr 22, 2026 | CVE Modified | CISA-ADP |
| Apr 22, 2026 | New CVE Received | [email protected] |