Service interruption via unbounded TC-deferred query queues
Published Jul 17, 2026 · Updated Jul 17, 2026
Denial of service in zeroconf before 0.149.12 allows remote attackers to interrupt mDNS consumers via local-link UDP/5353. AsyncListener.handle_query_or_defer stores uncapped TC-bit queries by source address and performs a linear duplicate scan for each arrival. Local-link access is required; distinct queries and spoofed sources drive memory growth, quadratic CPU use, and eventual process termination.
Summary
What happened
Denial of service in zeroconf before 0.149.12 allows remote attackers to interrupt mDNS consumers via local-link UDP/5353. AsyncListener.handle_query_or_defer stores uncapped TC-bit queries by source address and performs a linear duplicate scan for each arrival. Local-link access is required; distinct queries and spoofed sources drive memory growth, quadratic CPU use, and eventual process termination.
The record
- CVE
- CVE-2026-48045
- Published
- Jul 17, 2026
- Updated
- Jul 17, 2026
- Vendor
- python-zeroconf
- Product
- python-zeroconf
- Classifications
- CWE-770, T1499.004
- 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?
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- Affected versionversion=< 0.149.12
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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