Vulnerability · Published Jun 25, 2026 · Assigned by OX
CVE-2026-40208Denial of service via DoH3 queries
Low 3.7
In plain English
A low-severity security flaw in DNSdist from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.4%top 65.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
An attacker might be able to delay the processing of DoH3 queries by sending DoH3 GET queries with an invalid DATA frame.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | dnsdist | no fix listed | DEBIAN-CVE-2026-40208 |
| Debian:13 | dnsdist | 1.9.15-0+deb13u1 | DEBIAN-CVE-2026-40208 |
| Debian:14 | dnsdist | 2.1.0-1 | DEBIAN-CVE-2026-40208 |
| Ubuntu:25.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-40208 |
| Ubuntu:26.04:LTS | dnsdist | no fix listed | UBUNTU-CVE-2026-40208 |
| Ubuntu:26.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-40208 |
Affected products (as reported)
Weakness: CWE-705 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L