CVE-2026-33599
Received Received - Intake
SVCB Response Spoofing in Open-Xchange DDR Upgrade Mechanism

Publication date: 2026-04-22

Last updated on: 2026-04-24

Assigner: Open-Xchange

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.
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Meta Information
Published
2026-04-22
Last Modified
2026-04-24
Generated
2026-06-16
AI Q&A
2026-04-22
EPSS Evaluated
2026-06-15
NVD
CVE-2026-33599
EUVD
EUVD-2026-24941
Affected Vendors & Products
Showing 2 associated CPEs
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
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.
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Executive Summary

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.

Impact Analysis

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.

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