VDB
CVE-2026-11721
CVE-2026-11721
PUBLISHED
CVSS 7.5 HIGH
Reported by isc · Published July 22, 2026
It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default). This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
Risk Scores
CVSS 3.1
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| ISC | BIND 9 | 9.11.0, 9.20.0, 9.21.0 |
| ISC | BIND 9 | 9.20.9-S1, 9.11.3-S1, 9.21.0 |
| alpine | bind | 0, 0, 0 |
| isc | bind | 9.20.9-S1, 9.11.3-S1, 9.21.0 |
Timeline
- Jul 22, 2026 Coalition ESS Score
- Jul 22, 2026 CVE Published
- Jul 22, 2026 CVE Updated
- Jul 23, 2026 Security Advisory
- Jul 25, 2026 EPSS Score
References
- CVE-2026-11721 vendor-advisory
- patch
- patch