LAN-local memory exhaustion via unbounded DNS cache
Published Jul 17, 2026 · Updated Jul 17, 2026
Uncontrolled resource consumption in python-zeroconf before 0.149.7 allows remote attackers to exhaust memory via multicast mDNS responses. DNSCache._async_add stores every response record in the main cache, expiration map and heap, and service cache without limiting their entry counts. Any unauthenticated host on the local link can flood unique names or replay records with changing TTLs, slowing discovery callbacks or terminating a memory-constrained process.
Summary
What happened
Uncontrolled resource consumption in python-zeroconf before 0.149.7 allows remote attackers to exhaust memory via multicast mDNS responses. DNSCache._async_add stores every response record in the main cache, expiration map and heap, and service cache without limiting their entry counts. Any unauthenticated host on the local link can flood unique names or replay records with changing TTLs, slowing discovery callbacks or terminating a memory-constrained process.
The record
- CVE
- CVE-2026-47184
- Published
- Jul 17, 2026
- Updated
- Jul 17, 2026
- Vendor
- python-zeroconf
- Product
- python-zeroconf
- Classifications
- CWE-770, T1499.002
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 17, 2026CVE publishedPublication date reported by the CVE source.
- Jul 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.149.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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