CVE-2026-27854
Received Received - Intake
Use-After-Free in DNSdist Lua getEDNSOptions Causes DoS

Publication date: 2026-03-31

Last updated on: 2026-04-14

Assigner: Open-Xchange

Description
An attacker might be able to trigger a use-after-free by sending crafted DNS queries to a DNSdist using the DNSQuestion:getEDNSOptions method in custom Lua code. In some cases DNSQuestion:getEDNSOptions might refer to a version of the DNS packet that has been modified, thus triggering a use-after-free and potentially 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
2026-06-14
NVD
CVE-2026-27854
EUVD
EUVD-2026-17409
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-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

This vulnerability involves a use-after-free condition in DNSdist when processing DNS queries. Specifically, an attacker can send specially crafted DNS queries that exploit the DNSQuestion:getEDNSOptions method used in custom Lua code. In some cases, this method may reference a modified version of the DNS packet, leading to a use-after-free scenario.

This use-after-free can cause the DNSdist process to crash, resulting in a denial of service.

Impact Analysis

The primary impact of this vulnerability is the potential for denial of service. An attacker exploiting this flaw can cause DNSdist to crash by triggering the use-after-free condition, which may disrupt DNS services relying on DNSdist.

The CVSS score indicates a low to medium severity with limited confidentiality impact and no integrity impact, but it does have an availability impact.

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