CVE-2026-40208
LOWDescription
An attacker might be able to delay the processing of DoH3 queries by sending DoH3 GET queries with an invalid DATA frame.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 11% of all known CVEs.
References
Related Vulnerabilities
Other CWE-705 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-9848 | High | 7.3 | 0.6% | - | - |
| CVE-2024-45433 | Medium | 6.5 | 0.5% | - | - |
| CVE-2026-3264 | Medium | 6.3 | 0.4% | - | - |
| CVE-2026-3262 | Medium | 6.3 | 0.4% | - | - |
| CVE-2025-53856 | High | 7.5 | 0.3% | - | Fix |
| CVE-2026-10271 | Medium | 6.3 | 0.3% | - | - |
Common questions
How do I fix CVE-2026-40208?
Upgrade dnsdist on debian 13 to 1.9.15-0+deb13u1 or later.
Is CVE-2026-40208 being actively exploited?
Not that we know of. CVE-2026-40208 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.21% is the estimated probability that it will be exploited in the next 30 days. That is higher than 11% of all scored CVEs.
How severe is CVE-2026-40208?
CVE-2026-40208 has a CVSS v3 base score of 3.7, rated low. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-40208 affect?
Published advisories record a fix for dnsdist (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-40208
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-25.