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Medium 5.3Published Jun 25, 2026

CVE-2026-40211An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away.

Updated under an hour ago ()

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No exploitation reported and no EPSS estimate yet.

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.

CVSS
5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-770
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Not given
NVD analysis
Deferred
Record last updated
Jun 25, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

No affected products are listed yet.

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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