The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.
| Vendor | Product | Versions |
|---|---|---|
| isc | bind | 9.20.0, 9.21.0, 9.20.9-S1 |
Downstream vendors/products affected by this vulnerability
| Vendor | Product | Source | Confidence |
|---|---|---|---|
| debian | debian linux | cert_advisory | 90% |
| internet systems consortium | bind | cert_advisory | 90% |
Severity corrected from HIGH to CRITICAL based on vendor classification in new source
Initial creation
