CVE-2026-11721
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.
Impact
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.
Affected products
| Product | Affected versions |
|---|---|
| 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. |
Versions were read from the advisory text. No structured product data has been published for this record yet.