🛡️ CVE-2026-42004 on Debian — dnsdist

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

An attacker can send a crafted EDNS OPT record that will be ignored by DNSdist’s filtering rules, but will be rewritten as a valid OPT record when EDNS Client Subnet is inserted, causing the backend to see the EDNS option(s) that DNSdist did not filter.

Distribution advisory

This page covers CVE-2026-42004 as tracked by Debian, for the package dnsdist. The fix is available in version 2.1.0-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.

Affected software

DEBIAN-CVE-2026-42004 is recorded against 1 package.

  • dnsdist (fixed in 2.1.0-1)

Timeline and source

Published on 25 June 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-25
Updated 2026-08-12
Modified 2026-08-04
Fix URL N/A

Affected Packages

Software From version Fixed in
dnsdist — 2.1.0-1

Similar Threats

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