CVE-2026-47180

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

MEDIUM
6.5
CVSS Score
Published: July 17, 2026 at 06:21 PM UTC
Updated: August 17, 2026 at 08:05 PM UTC
2 products affected across 2 vendorsZeroconfZeroconf

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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 / ff02::fb). This issue is fixed in version 0.149.5.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.149.5
Affected range stops below 0.149.5, so it looks safe — our inference, not a vendor statement
v < 0.149.5
Affected range stops below 0.149.5, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-674

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