CVE-2026-42004
EDNS options smuggling
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.
INFO
Published Date :
June 25, 2026, 12:24 p.m.
Last Modified :
June 25, 2026, 12:24 p.m.
Remotely Exploit :
Yes !
Source :
OX
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | 8ce71d90-2354-404b-a86e-bec2cc4e6981 | ||||
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update DNSdist to the latest version.
- Review and apply EDNS Client Subnet filtering rules.
- Test filtering with crafted EDNS OPT records.
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CVE-2026-42004 vulnerability anywhere in the article.