CVE-2026-47180 is a medium-severity security vulnerability in zeroconf (pip), affecting versions < 0.149.5. It is fixed in 0.149.5.
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's default limit, and RecursionError was not listed in DECODE_EXCEPTIONS, so it escaped DNSIncoming.init and was logged by asyncio's default exception handler. Any unauthenticated host on the local link (UDP/5353, 224.0.0.251 / ff02::fb) can degrade the mDNS listener; that includes a guest on the same Wi-Fi, a compromised IoT device, or a container on a shared bridge. Replaying at a few hertz produces sustained CPU burn and log flooding, and mDNS-dependent features (HomeKit, Chromecast/Matter, AirPlay, printers) degrade while the attack is in flight. Patches Fixed in zeroconf 0.149.5 (PR #1719). Upgrade to >= 0.149.5. Workarounds There is no in-process workaround; upgrading is the fix. Otherwise, restrict mDNS (UDP/5353) to trusted Layer-2 segments via AP client isolation, guest-network separation, or host firewall rules. Resources PR #1719, fix Issue #1713, public tracking issue RFC 1035 §4.1.4, RFC 6762, CWE-674
CVE-2026-47180 has a CVSS score of 6.5 (Medium). The vector is reachable from an adjacent network, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (0.149.5). Upgrading removes the vulnerable code path.
pip
zeroconf (< 0.149.5)zeroconf → 0.149.5 (pip)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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CVE-2026-47180 is a medium-severity security vulnerability in zeroconf (pip), affecting versions < 0.149.5. It is fixed in 0.149.5.
CVE-2026-47180 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
zeroconf (pip) versions < 0.149.5 is affected.
Yes. CVE-2026-47180 is fixed in 0.149.5. Upgrade to this version or later.
Whether CVE-2026-47180 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade zeroconf to 0.149.5 or later.