Vulnerability · Published Mar 31, 2026 · Assigned by OX
CVE-2026-27854Use after free when parsing EDNS options in Lua
Medium 4.8
In plain English
A medium-severity use-after-free in DNSdist from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | dnsdist | 2.0.4-r0 | ALPINE-CVE-2026-27854 |
| Alpine:v3.24 | dnsdist | 2.0.4-r0 | ALPINE-CVE-2026-27854 |
| Debian:12 | dnsdist | no fix listed | DEBIAN-CVE-2026-27854 |
| Debian:13 | dnsdist | 1.9.14-0+deb13u1 | DEBIAN-CVE-2026-27854 |
| Debian:14 | dnsdist | 2.0.3-1 | DEBIAN-CVE-2026-27854 |
| Ubuntu:25.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-27854 |
| Ubuntu:26.04:LTS | dnsdist | no fix listed | UBUNTU-CVE-2026-27854 |
| Ubuntu:26.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-27854 |
Affected products (as reported)
Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L