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: 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 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 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-2026-60047

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...

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-2026-60045

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...

OESA-2026-2833 python-zeroconf security update

Pure Python Multicast DNS Service Discovery Library Bonjour/Avahi compatible Security Fixes: 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...

OESA-2026-2832 python-zeroconf security update

Pure Python Multicast DNS Service Discovery Library Bonjour/Avahi compatible Security Fixes: 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...

openSUSE 16 Security Update : python-zeroconf (openSUSE-SU-2026:21175-1)

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21175-1 advisory. Changes in python-zeroconf: - CVE-2026-47180: zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial o...

Security update for python-zeroconf (moderate)

openSUSE security update: security update for python-zeroconf ------------------------------------------------------------- Announcement ID: openSUSE-SU-2026:21175-1 Rating: moderate References: bsc1268235 bsc1268341 bsc1268342 bsc1268343 bsc1268388 Cross-References: CVE-2026-47180 CVE-2026-47183...

OPENSUSE-SU-2026:21175-1 Security update for python-zeroconf

This update for python-zeroconf fixes the following issues: Changes in python-zeroconf: - CVE-2026-47180: zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service bsc1268341 - CVE-2026-47183: zeroconf: Unbounded exception-dedup state retains pack...

GHSA-QC2X-6F54-M6H9 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...

Improper Handling of Length Parameter Inconsistency

Overview zeroconf is a Pure Python Multicast DNS Service Discovery Library Bonjour/Avahi compatible Affected versions of this package are vulnerable to Improper Handling of Length Parameter Inconsistency via the readcharacterstring and readstring functions. An attacker can inject malicious...

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...