dnscache in Daniel J. Bernstein djbdns 1.05 does not prevent simultaneous identical outbound DNS queries, which makes it easier for remote attackers to spoof DNS responses, as demonstrated by a spoofed A record in the Additional section of a response to a Start of Authority (SOA) query.
Concurrent Execution using Shared Resource with Improper Synchronization The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.