PatchTheCVECVE-2022-40188: Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because of a
CVE-2022-40188 is a high-severity flaw (CVSS 7.5) affecting knot resolver, fedora, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because of algorithmic complexity. During an attack, an authoritative server must return large NS sets or address sets.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.9% (top 20%) |
| CISA exploited list | No |
| Weakness | CWE-407 |
| Published | 2022-09-23 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2022-40188?
knot resolver: upgrade to 5.5.3; fedora: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2022-40188 being exploited?
CVE-2022-40188 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2022-40188 affect?
CVE-2022-40188 affects knot resolver, fedora, debian linux. Severity is high (CVSS 7.5). Knot Resolver before 5.5.3 allows remote attackers to cause a denial of service (CPU consumption) because of algorithmic complexity. During an attack, an authoritative server must return large NS sets or address sets.
How urgent is CVE-2022-40188?
Priority 56/100. High severity; Remotely exploitable, no login, no user action; On your watchlist
Software pages
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