Misinterpretation of Input in dnsdist - CVE-2026-42004
Published: June 25, 2026
Vulnerability identifier: #VU135337
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-42004
CWE-ID: CWE-115
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: PowerDNS.COM B.V.
Affected software:
dnsdist
dnsdist
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass security rules.
The vulnerability exists due to improper neutralization of EDNS options in EDNS option filtering when processing crafted DNS queries with a crafted EDNS OPT record while EDNS Client Subnet is inserted. A remote attacker can send a crafted EDNS OPT record to bypass security rules.
The backend can receive EDNS options that were not filtered by DNSdist.
How to mitigate CVE-2026-42004
Install security update from vendor's website.