Hickory DNS from 0.26.0 before 0.26.2 Panic via TSIG RDATA Decoding

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

Hickory DNS from 0.26.0 before 0.26.2 contains an integer underflow vulnerability in TSIG RDATA decoding that allows remote attackers to trigger a panic via malformed records. Attackers can send a crafted TSIG record in DNS wire format to cause unchecked subtraction underflow, crashing builds with overflow checks enabled and causing denial of service.

When a TSIG record is decoded from the DNS wire format, its MAC length and "other data" length are checked against the end of the record data. If a check failed, the error value was built from `end_idx - decoder.index()`. For a malformed record the decoder can already be past `end_idx`, so this unsigned subtraction underflows. In builds with overflow checks enabled (the `dev` profile by default) the underflow panics, so a peer that sends a crafted TSIG record can crash the process. In builds without overflow checks the result wraps and is only used in the returned error. The fix returns a plain "insufficient bytes" error without the subtraction. It is in 0.26.2.