CVE-2026-27854 PUBLISHED

Use after free when parsing EDNS options in Lua

Assigner: OX
Reserved: 24.02.2026 Published: 31.03.2026 Updated: 31.03.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
CVSS Score: 4.8

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	PowerDNS
Product	DNSdist
Versions	Default: unaffected affected from 1.9.0 to 1.9.12 (excl.) affected from 2.0.0 to 2.0.3 (excl.)

Credits

Naoki Wakamatsu finder

References

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html

Problem Types

Use After Free CWE