CVE-2026-33599
SVCB Response Spoofing in Open-Xchange DDR Upgrade Mechanism
Publication date: 2026-04-22
Last updated on: 2026-04-24
Assigner: Open-Xchange
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| powerdns | dnsdist | From 1.9.0 (inc) to 1.9.13 (exc) |
| powerdns | dnsdist | From 2.0.0 (inc) to 2.0.4 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-125 | The product reads data past the end, or before the beginning, of the intended buffer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability involves a rogue backend sending a specially crafted SVCB response to a Discovery of Designated Resolvers (DDR) request. This occurs when the request is made using either the autoUpgrade (Lua) option to newServer or the auto_upgrade (YAML) settings. It is important to note that DDR upgrade is not enabled by default.
How can this vulnerability impact me? :
The impact of this vulnerability is limited. According to the CVSS v3.1 score, it has a base score of 3.1, indicating a low severity. The attack vector is adjacent network, with high attack complexity, no privileges required, no user interaction, and it only affects availability (causing a partial denial of service). There is no impact on confidentiality or integrity.