GHSA-9pgc-3ccv-5297

Suggest an improvement
Source
https://github.com/advisories/GHSA-9pgc-3ccv-5297
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9pgc-3ccv-5297/GHSA-9pgc-3ccv-5297.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-9pgc-3ccv-5297
Aliases
  • CVE-2026-47180
Published
2026-05-29T20:09:52Z
Modified
2026-05-29T20:15:14.866644739Z
Severity
  • 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
zeroconf has unbounded recursion in DNS compression-pointer decoder that allows LAN-local denial of service
Details

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 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

Database specific 
{
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-29T20:09:52Z",
    "nvd_published_at": null,
    "severity": "MODERATE",
    "cwe_ids": [
        "CWE-674"
    ]
}
References

Affected packages

PyPI / zeroconf

Package

Name
zeroconf
View open source insights on deps.dev
Purl
pkg:pypi/zeroconf

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
0.149.5

Affected versions

0.*
0.14
0.15
0.15.1
0.16.0
0.17.0
0.17.1
0.17.2
0.17.3
0.17.4
0.17.5
0.17.6
0.17.7
0.18.0
0.19.0
0.19.1
0.20.0
0.21.0
0.21.1
0.21.2
0.21.3
0.22.0
0.23.0
0.24.0
0.24.1
0.24.2
0.24.3
0.24.4
0.24.5
0.25.0
0.25.1
0.26.0
0.26.1
0.26.2
0.26.3
0.27.0
0.27.1
0.28.0
0.28.1
0.28.2
0.28.3
0.28.4
0.28.5
0.28.6
0.28.7
0.28.8
0.29.0
0.30.0
0.31.0
0.32.0
0.32.1
0.33.0
0.33.1
0.33.2
0.33.3
0.33.4
0.34.0
0.34.1
0.34.2
0.34.3
0.35.0
0.35.1
0.36.0
0.36.1
0.36.2
0.36.3
0.36.4
0.36.5
0.36.6
0.36.7
0.36.8
0.36.9
0.36.11
0.36.12
0.36.13
0.37.0
0.38.0
0.38.1
0.38.3
0.38.4
0.38.5
0.38.6
0.38.7
0.39.0
0.39.1
0.39.2
0.39.3
0.39.4
0.43.0
0.44.0
0.45.0
0.46.0
0.47.0
0.47.1
0.47.2
0.47.3
0.47.4
0.48.0
0.49.0
0.50.0
0.51.0
0.52.0
0.53.0
0.53.1
0.54.0
0.55.0
0.56.0
0.57.0
0.58.0
0.58.1
0.58.2
0.59.0
0.60.0
0.61.0
0.62.0
0.63.0
0.64.0
0.64.1
0.65.0
0.66.0
0.67.0
0.68.0
0.68.1
0.69.0
0.70.0
0.71.0
0.71.1
0.71.2
0.71.3
0.71.4
0.71.5
0.72.0
0.72.1
0.72.2
0.72.3
0.73.0
0.74.0
0.75.0
0.76.0
0.77.0
0.78.0
0.79.0
0.80.0
0.81.0
0.82.0
0.82.1
0.83.0
0.83.1
0.84.0
0.85.0
0.86.0
0.87.0
0.88.0
0.89.0
0.90.0
0.91.0
0.91.1
0.92.0
0.93.0
0.93.1
0.94.0
0.95.0
0.96.0
0.97.0
0.98.0
0.99.0
0.100.0
0.101.0
0.102.0
0.103.0
0.104.0
0.105.0
0.106.0
0.107.0
0.108.0
0.109.0
0.110.0
0.111.0
0.112.0
0.114.0
0.115.0
0.115.1
0.115.2
0.116.0
0.117.0
0.118.0
0.118.1
0.119.0
0.120.0
0.121.0
0.122.0
0.122.1
0.122.2
0.122.3
0.123.0
0.124.0
0.125.0
0.126.0
0.127.0
0.128.0
0.128.1
0.128.2
0.128.3
0.128.4
0.128.5
0.129.0
0.130.0
0.131.0
0.132.0
0.132.1
0.132.2
0.133.0
0.134.0
0.135.0
0.136.0
0.136.1
0.136.2
0.137.0
0.137.1
0.137.2
0.138.0
0.138.1
0.139.0
0.140.0
0.140.1
0.141.0
0.142.0
0.143.0
0.143.1
0.144.0
0.144.1
0.144.2
0.144.3
0.145.0
0.145.1
0.146.0
0.146.1
0.146.2
0.146.3
0.146.4
0.146.5
0.147.0
0.147.1
0.147.2
0.147.3
0.147.4
0.148.0
0.149.0
0.149.1
0.149.2
0.149.3
0.149.4

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9pgc-3ccv-5297/GHSA-9pgc-3ccv-5297.json"