Buffer over-read in dnsdist - CVE-2026-40210
Published: June 25, 2026
Vulnerability identifier: #VU135340
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-40210
CWE-ID: CWE-126
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 disclose sensitive information or cause a denial of service.
The vulnerability exists due to out-of-bounds read in SetMacAddrAction when processing DNS queries while SetMacAddrAction is used. A remote attacker can send DNS queries to disclose sensitive information or cause a denial of service.
The issue can result in uninitialized memory being sent over the network or a crash.
How to mitigate CVE-2026-40210
Install security update from vendor's website.