CVE-2026-33596
Received Received - Intake

Query Mismatch Vulnerability in Open-Xchange TCP/DNS Backends

Vulnerability report for CVE-2026-33596, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-04-22

Last updated on: 2026-04-24

Assigner: Open-Xchange

Description

A client might theoretically be able to cause a mismatch between queries sent to a backend and the received responses by sending a flood of perfectly timed queries that are routed to a TCP-only or DNS over TLS backend.

CVSS Scores

EPSS Scores

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Percentile:

Meta Information

Published
2026-04-22
Last Modified
2026-04-24
Generated
2026-07-06
AI Q&A
2026-04-22
EPSS Evaluated
2026-07-05
NVD
EUVD

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-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

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Executive Summary

This vulnerability involves a client potentially causing a mismatch between queries sent to a backend and the responses received. This can happen if the client sends a flood of perfectly timed queries that are routed to a backend using either TCP-only or DNS over TLS.

Impact Analysis

The impact of this vulnerability is limited to availability, as indicated by the CVSS score. It could cause disruptions or delays in receiving correct responses from the backend due to mismatched queries and responses, potentially leading to degraded service or denial of service conditions.

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EPSS Chart