Hickory-DNS 0.26.0 before 0.26.2 UDP Client Denial of Service via Spoofed Responses

published 2026-09-03 2mo ago modified 2026-11-10 yesterday also EUVD-2026-119343 , GHSA-v44v-c8m4-gc43

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository hickory-dns/hickory-dns. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss: 5.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits: 0; none known

The hickory-net crate in Hickory DNS 0.26.0 before 0.26.2 stops listening and returns an error when a client UDP connection receives a datagram that cannot be parsed as a DNS message. Remote attackers who guess the query's source port, without knowing the transaction ID, can spoof malformed responses to abort client queries, causing denial of service.

Patch / fix

fixed in 1 distros 1

hickory-dns hickory-dns 0.26.2

rust-hickory-net Debian 14 0.26.3-1

debian advisories DEBIAN-CVE-2026-123584

Is CVE-2026-123584 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.2	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA	4.0	8.2	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

hickory-dns hickory-dns

Classification

Weakness

CWE-696 Incorrect Behavior Order

References

github.com /hickory-dns/hickory-dns/security/advisories/GHSA-v44v-c8m4-gc43
vendor-advisory, advisory
vulncheck.com /advisories/hickory-dns-0.26.0-before-0.26.2-udp-client-denial-of-service-via-spoofed-responses
third-party-advisory

Sources

CVE List CVE-2026-123584
NVD CVE-2026-123584
Maintainer advisory GHSA-v44v-c8m4-gc43

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of hickory-dns/hickory-dns published their own advisory on GitHub. Reviewed sources take precedence over it.