A use-after-return vulnerability exists in the named server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.
This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.
BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.
Weakness
The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Bind | Isc | 9.20.0 (including) | 9.20.21 (excluding) |
| Bind | Isc | 9.21.0 (including) | 9.21.20 (excluding) |
| Red Hat Hardened Images | RedHat | bind-main-9.18.48-1.hum1 | * |
| Bind9 | Ubuntu | questing | * |
| Bind9 | Ubuntu | upstream | * |
| Isc-dhcp | Ubuntu | questing | * |