CVE-2026-77119

EUVD-2026-80787
A validly signed NSEC3 from an unrelated sibling zone may be accepted as an insecurity proof, downgrading a secure delegation and letting a forged unsigned answer through.
This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.9 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Debian logo
Debian Releases
Debian Product
Codename
bind9
bookworm
vulnerable
bookworm (security)
vulnerable
forky
vulnerable
sid
1:9.20.29-1
fixed
trixie
vulnerable
trixie (security)
vulnerable
Common Weakness Enumeration
References
https://downloads.isc.org/isc/bind9/9.20.29
https://downloads.isc.org/isc/bind9/9.21.26
https://kb.isc.org/docs/cve-2026-77119