CVE-2026-40211

Denial of service via crafted DoH3 queries

Medium · published June 25, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
52.6
In the wild
Unconfirmed
What it is

An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00700 · 52.6th percentile
Published
2026-06-25T12:23Z
EPSS history
Timeline
  • 25 JUN 12:23Z
    Denial of service via crafted DoH3 queries
    cvelistv5