A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer from runaway memory usage. The attacker needs to be able to send queries faster than the resolver can perform validation. The increased memory usage can be orders of magnitude beyond the limit configured in the `max-cache-size` parameter. 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.
| Vendor | Product | Versions |
|---|---|---|
| isc | bind | 9.11.0, 9.20.0, 9.21.0, 9.11.3-S1, 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 updated from HIGH to CRITICAL based on vendor classification in new article.
Initial creation
