Bug 2508069

Summary: CVE-2026-47180 python-zeroconf: Zeroconf: Denial of Service via crafted mDNS packets [fedora-all]
Product: [Fedora] Fedora Reporter: jkelly <jkelly>
Component: python-zeroconfAssignee: Miro Hrončok <mhroncok>
Status: CLOSED NEXTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: 45CC: mhroncok, pbrobinson, python-packagers-sig
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["2c927654-f05a-4aff-9105-6cdfada5c897"]}
Fixed In Version: Doc Type: ---
Doc Text:
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Clone Of: Environment:
Last Closed: 2026-08-29 10:11:44 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2501850    

Description jkelly 2026-07-28 16:17:37 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.
Comment 1 Aoife Moloney 2026-08-17 15:39:33 UTC 
This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.
Comment 2 Peter Robinson 2026-08-29 10:11:44 UTC 
Fixed in F-45+ because it's not possible to upgrade earlier releases without significant effort due to dependencies on newer protobuf releases not in older versions of Fedora.