Medium
Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-47180
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 15:50 UTC · Revision 1
Source evidence
Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service
core-osv · Original sourcePublished 17 Jul 2026, 18:21 UTC
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.
osv:CVE-2026-47180
Complete source record
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"url": "https://osv.dev/vulnerability/CVE-2026-47180",
"method": "structured",
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"title": "Zeroconf: Unbounded recursion in DNS compression-pointer decoder allows LAN-local denial of service",
"summary": "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.",
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"PYSEC-2026-3436"
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"modified": "2026-10-28T02:30:30.166982473Z",
"provider": "osv",
"references": [
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