CVE-2026-27853
Received Received - Intake
Out-of-Bounds Write in DNSdist Lua Causes Denial of Service

Publication date: 2026-03-31

Last updated on: 2026-04-14

Assigner: Open-Xchange

Description
An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.
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Meta Information
Published
2026-03-31
Last Modified
2026-04-14
Generated
2026-06-16
AI Q&A
2026-03-31
EPSS Evaluated
2026-06-15
NVD
CVE-2026-27853
EUVD
EUVD-2026-17407
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
powerdns dnsdist From 1.9.0 (inc) to 1.9.12 (exc)
powerdns dnsdist From 2.0.0 (inc) to 2.0.3 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.
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Executive Summary

This vulnerability involves an attacker sending specially crafted DNS responses to a DNSdist service that uses custom Lua code with the DNSQuestion:changeName or DNSResponse:changeName methods. These crafted responses can trigger an out-of-bounds write, which means the program writes data outside the intended memory area.

In some cases, the rewritten DNS packet may become larger than the original response and can even exceed the maximum allowed size of 65535 bytes. This can cause the DNSdist service to crash.

The crash results in a denial of service condition, where legitimate users may be unable to use the DNSdist service.

Impact Analysis

The primary impact of this vulnerability is a denial of service (DoS) condition. An attacker exploiting this issue can cause the DNSdist service to crash by sending malicious DNS responses.

This can disrupt DNS resolution services relying on DNSdist, potentially leading to service outages or degraded network performance.

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