CVE-2026-47183 Zeroconf: Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.6, DNSIncoming.logexceptiondebug and the four QuietLogger exception-dedup methods stored an unbounded seenlogs dictionary keyed by attacker-influenced IncomingDecodeError messages, retaining sys.excinfo...

CVE-2026-47180 Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.init, causing...

CVE-2026-47180

CVE-2026-47180 affects the Zeroconf Python library. The vulnerability stems from DNSIncoming._decode_labels_at_offset recursing for each DNS-name compression pointer; a crafted mDNS packet with ~1500 chained pointers can cause unbounded recursion, escaping DNSIncoming.init and triggering sustaine...

CVE-2026-47180

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.init, causing...

CVE-2026-47180 Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.init, causing...

PYSEC-2026-3438 zeroconf: Unvalidated rdlength in record payload readers allows LAN-local cache corruption via crafted mDNS packet

Impact readcharacterstring and readstring in src/zeroconf/protocol/incoming.py sliced self.dataself.offset : self.offset + length and advanced self.offset by the declared length without checking it against self.datalen. Python's slice silently returns fewer bytes when the end index runs past the...

zeroconf: Unvalidated rdlength in record payload readers allows LAN-local cache corruption via crafted mDNS packet

Impactreadcharacterstring and readstring in src/zeroconf/protocol/incoming.py sliced self.dataself.offset : self.offset + length and advanced self.offset by the declared length without checking it against self.datalen. Python's slice silently returns fewer bytes when the end index runs past the...

python-zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source flood

ImpactAsyncListener.handlequeryordefer retained every truncated TC-bit incoming query in self.deferredaddr and armed a per-addr timer in self.timersaddr that flushed the reassembled query within 500 ms RFC 6762 §18.5. Neither the per-addr list nor the number of distinct addr keys was capped, and...

PYSEC-2026-3435 python-zeroconf: Unbounded TC-deferred queue allows LAN-local memory exhaustion via spoofed-source flood

Impact AsyncListener.handlequeryordefer retained every truncated TC-bit incoming query in self.deferredaddr and armed a per-addr timer in self.timersaddr that flushed the reassembled query within 500 ms RFC 6762 §18.5. Neither the per-addr list nor the number of distinct addr keys was capped, and...

zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service

ImpactDNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer RFC 1035 §4.1.4. Pointer cycles and label counts were capped, but the chain length of unique forward pointers was not. A single 3 kB mDNS packet carrying 1500 chained pointers drives the recursion past CPython's...

zeroconf: Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion

ImpactDNSIncoming.logexceptiondebug and the four QuietLogger exception-dedup methods stored an unbounded seenlogs dict keyed by strsys.excinfo1. The seven IncomingDecodeError messages raised from readname / decodelabelsatoffset RFC 6762 §18 name-decoding error paths all embed self.source — the...

zeroconf has unbounded DNS record cache that allows LAN-local memory exhaustion via multicast flood

ImpactDNSCache.asyncadd inserted every response record into cache, expirations, expireheap, and servicecache with no cap on entry count. The only pre-existing protection was a PTR TTL floor DNSPTRMINTTL = 1125 s, RFC 6762 §10, which actually prolonged attacker-injected records, and a periodic...

PYSEC-2026-3436 zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service

Impact DNSIncoming.decodelabelsatoffset recurses once per DNS-name compression pointer RFC 1035 §4.1.4. Pointer cycles and label counts were capped, but the chain length of unique forward pointers was not. A single 3 kB mDNS packet carrying 1500 chained pointers drives the recursion past CPython'...

PYSEC-2026-3437 zeroconf: Unbounded exception-dedup state retains packet buffers via traceback frame locals, enabling LAN-local memory exhaustion

Impact DNSIncoming.logexceptiondebug and the four QuietLogger exception-dedup methods stored an unbounded seenlogs dict keyed by strsys.excinfo1. The seven IncomingDecodeError messages raised from readname / decodelabelsatoffset RFC 6762 §18 name-decoding error paths all embed self.source — the...

PYSEC-2026-3439 zeroconf has unbounded DNS record cache that allows LAN-local memory exhaustion via multicast flood

Impact DNSCache.asyncadd inserted every response record into cache, expirations, expireheap, and servicecache with no cap on entry count. The only pre-existing protection was a PTR TTL floor DNSPTRMINTTL = 1125 s, RFC 6762 §10, which actually prolonged attacker-injected records, and a periodic...

PT-2026-60048

Impact DNSCache. async add inserted every response record into cache, expirations, expire heap, and service cache with no cap on entry count. The only pre-existing protection was a PTR TTL floor DNS PTR MIN TTL = 1125 s, RFC 6762 §10, which actually prolonged attacker-injected records, and a...

PT-2026-60046

Impact DNSIncoming. log exception debug and the four QuietLogger exception-dedup methods stored an unbounded seen logs dict keyed by strsys.exc info1. The seven IncomingDecodeError messages raised from read name / decode labels at offset RFC 6762 §18 name-decoding error paths all embed self.sourc...

PT-2026-60045

Impact DNSIncoming. decode labels at offset recurses once per DNS-name compression pointer RFC 1035 §4.1.4. Pointer cycles and label counts were capped, but the chain length of unique forward pointers was not. A single 3 kB mDNS packet carrying 1500 chained pointers drives the recursion past...

PT-2026-60044

Impact AsyncListener.handle query or defer retained every truncated TC-bit incoming query in self. deferredaddr and armed a per-addr timer in self. timersaddr that flushed the reassembled query within 500 ms RFC 6762 §18.5. Neither the per-addr list nor the number of distinct addr keys was capped...

PT-2026-60047

Impact read character string and read string in src/zeroconf/ protocol/incoming.py sliced self.dataself.offset : self.offset + length and advanced self.offset by the declared length without checking it against self. data len. Python's slice silently returns fewer bytes when the end index runs pas...