Low severity · published Jun 25, 2026
CVE-2026-42004
EDNS options smuggling
3.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DN
DNSdist · PowerDNS
1.9.0 before 1.9.15; 2.0.0 before 2.0.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42004
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42004
www.dnsdist.org
https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html
More from DNSdist
9.1
CVE-2026-33598
Out-of-bounds read in cache inspection via Lua
8.8
CVE-2017-7557
dnsdist version 1.1.0 is vulnerable to a flaw in authentication mechanism for REST API potentially allowing CSRF attack
8.2
CVE-2026-33602
Off-by-one access when processing crafted UDP responses
8.2
CVE-2026-24028
Out-of-bounds read when parsing DNS packets via Lua
8.1
CVE-2026-33599
Out-of-bounds read in service discovery