CVE-2026-47180: Zeroconf is a pure Python implementation of multicast DNS service discovery

Routine

MEDIUM 6.5UPGRADE

CVE-2026-47180 is a medium-severity flaw (CVSS 6.5) affecting zeroconf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigger a RecursionError that escapes DNSIncoming.__init__, causing sustained CPU burn, log flooding, and degraded mDNS-dependent features for unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff0

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-674
Published	2026-07-17
Last modified	2026-08-17

Publisher (CNA): GitHub, Inc. · Vendor: paulsm

Last updated 2026-08-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 19:17 UTCPublished CVE record published
2026-08-17 19:48 UTCUpdated Record last modified

paulsm zeroconf UPGRADE

Affected: < 0.149.5

Fixed in: 0.149.5

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show zeroconf

2. UPGRADE to 0.149.5

pip install --upgrade "zeroconf>=0.149.5"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-47180?

zeroconf: upgrade to 0.149.5. Exact commands for each OS are on this page.

Is CVE-2026-47180 being exploited?

CVE-2026-47180 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-47180 affect?

CVE-2026-47180 affects zeroconf. Severity is medium (CVSS 6.5). Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.5, DNSIncoming._decode_labels_at_offset recurses once per DNS-name compression pointer, and a single mDNS packet carrying chained pointers can trigg

How urgent is CVE-2026-47180?

Priority 30/100. No elevated risk signals yet.

Software pages

Python vulnerabilities

Related CVEs

CVE-2026-48487 MEDIUM 5.3 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-48045 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-47184 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery
CVE-2026-47183 MEDIUM 6.5 UPGRADE Zeroconf is a pure Python implementation of multicast DNS service discovery

References

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