The issue is unexpected program termination based on ordering and/or specific content in responses to queries for CNAME or DNAME, and A records. Specifically, if a client queries for a DNAME and A record below the DNAME to the resolver, and the authoritative server responds positively to the A query but delays the DNAME response and later responds negatively, `named` may quit unexpectedly. Or, if a client queries for a CNAME and A record for the same name to the resolver, and the authoritative server responds positively to the A query but delays the CNAME response and later responds with a self-referential CNAME, the same failure may occur. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.
| Vendor | Product | Versions |
|---|---|---|
| isc | bind | 9.18.0, 9.20.0, 9.18.11-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 upgraded from HIGH to CRITICAL based on vendor classification in new article.
Initial creation
