Description
Knot Resolver before 6.4.1 allows remote code execution via a heap-based buffer overflow in the DoQ (DNS-over-QUIC) receive path.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nic | Knot Resolver | < 6.4.1 | 6.4.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | knot-resolver | 6.4.1-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | knot-resolver | No fix yet | — |
| Ubuntu 24.04 LTS | knot-resolver | No fix yet | — |
| Ubuntu 20.04 LTS | knot-resolver | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | knot-resolver | No fix yet | — |
| Ubuntu Pro 18.04 LTS | knot-resolver | No fix yet | — |
| Ubuntu Pro 16.04 LTS | knot-resolver | No fix yet | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
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venglin/knot-doq ★ 0 · Jul 23, 2026
CVE-2026-66374: Knot Resolver 6.3.0 DNS-over-QUIC heap overflow (RCE)
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.