Bug 2501840 (CVE-2026-48487)

Summary: CVE-2026-48487 zeroconf: Zeroconf: Data integrity vulnerability via malformed DNS records
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: eglynn, jjoyce, jpretori, jschluet, lhh, mburns, mgarciac
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Zeroconf, a Python library for multicast DNS service discovery. An unauthenticated attacker on the local network can exploit a vulnerability in how the system processes incoming DNS records. By sending a specially crafted record with an excessive length, the attacker can cause the system's DNS cache and service information to be populated with manipulated or truncated data. This could lead to incorrect service discovery or other data integrity issues within the affected system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2508073    
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Description OSIDB Bzimport 2026-07-17 19:01:43 UTC
Zeroconf is a pure Python implementation of multicast DNS service discovery. Prior to 0.149.16, _read_character_string and _read_string in src/zeroconf/_protocol/incoming.py advanced self.offset by attacker-declared RDLENGTH without checking it against self._data_len, allowing unauthenticated hosts on the local link over UDP/5353 (224.0.0.251 / ff02::fb) to send a TXT, HINFO, or A/AAAA record with rdlength=65535 and seed DNSCache and ServiceInfo.properties with truncated, attacker-shaped key/value or address records. This issue is fixed in version 0.149.16.