CVE-2026-81634

Name
CVE-2026-81634
Description
In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.
NVD Severity
unknown
Other trackers
CVE, NVD, CERT, CVE Details, CIRCL, Arch Linux, Debian, Red Hat, Ubuntu, Gentoo, SUSE (Bugzilla), SUSE (CVE), Mageia
Mailing lists
oss-security, full-disclosure, bugtraq
Exploits
Exploit DB, Metasploit
Forges
GitHub (code, issues), Aports (code, issues)

References

Type URI
Patch https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-81634.txt

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* unbound >= None < 1.26.1

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
unbound edge-main 1.26.1-r0 Jakub Jirutka <jakub@jirutka.cz> fixed
unbound edge-main 1.26.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.25.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.25.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.25.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.24.2-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.24.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.24.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.24.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.23.1-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.23.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.23.0-r2 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.23.0-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.23.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.22.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.21.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.20.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.19.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.19.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.16.3-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.16.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound edge-main 1.10.1-r0 None possibly vulnerable
unbound edge-main 1.9.5-r0 None possibly vulnerable
unbound edge-main 1.9.4-r0 None possibly vulnerable
unbound 3.24-main 1.25.2-r2 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.24-main 1.25.2-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.24-main 1.25.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.24-main 1.25.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.23-main 1.25.2-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.23-main 1.25.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.23-main 1.24.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.25.2-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.25.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.23.1-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.23.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.23.0-r2 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.22-main 1.21.1-r0 None possibly vulnerable
unbound 3.22-main 1.20.0-r0 None possibly vulnerable
unbound 3.22-main 1.19.2-r0 None possibly vulnerable
unbound 3.22-main 1.19.1-r0 None possibly vulnerable
unbound 3.22-main 1.16.3-r0 None possibly vulnerable
unbound 3.22-main 1.16.2-r0 None possibly vulnerable
unbound 3.22-main 1.10.1-r0 None possibly vulnerable
unbound 3.22-main 1.9.5-r0 None possibly vulnerable
unbound 3.22-main 1.9.4-r0 None possibly vulnerable
unbound 3.21-main 1.22.0-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.21-main 1.22.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.21-main 1.21.1-r0 None possibly vulnerable
unbound 3.21-main 1.20.0-r0 None possibly vulnerable
unbound 3.21-main 1.19.2-r0 None possibly vulnerable
unbound 3.21-main 1.19.1-r0 None possibly vulnerable
unbound 3.21-main 1.16.3-r0 None possibly vulnerable
unbound 3.21-main 1.16.2-r0 None possibly vulnerable
unbound 3.21-main 1.10.1-r0 None possibly vulnerable
unbound 3.21-main 1.9.5-r0 None possibly vulnerable
unbound 3.21-main 1.9.4-r0 None possibly vulnerable
unbound 3.20-main 1.20.0-r2 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.20-main 1.20.0-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.20-main 1.20.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.20-main 1.19.2-r0 None possibly vulnerable
unbound 3.20-main 1.19.1-r0 None possibly vulnerable
unbound 3.20-main 1.16.3-r0 None possibly vulnerable
unbound 3.20-main 1.16.2-r0 None possibly vulnerable
unbound 3.20-main 1.10.1-r0 None possibly vulnerable
unbound 3.20-main 1.9.5-r0 None possibly vulnerable
unbound 3.20-main 1.9.4-r0 None possibly vulnerable
unbound 3.19-main 1.20.0-r2 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.19-main 1.20.0-r1 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.19-main 1.20.0-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.19-main 1.19.2-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.19-main 1.19.1-r0 Jakub Jirutka <jakub@jirutka.cz> possibly vulnerable
unbound 3.19-main 1.16.3-r0 None possibly vulnerable
unbound 3.19-main 1.16.2-r0 None possibly vulnerable
unbound 3.19-main 1.10.1-r0 None possibly vulnerable
unbound 3.19-main 1.9.5-r0 None possibly vulnerable
unbound 3.19-main 1.9.4-r0 None possibly vulnerable