CVE-2019-9747
CVSS v3
7.5
HIGH
EPSS Score
1.4 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
In tinysvcmdns through 2018-01-16, a maliciously crafted mDNS (Multicast DNS) packet triggers an infinite loop while parsing an mDNS query. When mDNS compressed labels point to each other, the function uncompress_nlabel goes into an infinite loop trying to analyze the packet with an mDNS query. As a result, the mDNS server hangs after receiving the malicious mDNS packet. NOTE: the product's web site states "This project is un-maintained, and has been since 2013. ... There are known vulnerabilities ... You are advised to NOT use this library for any new projects / products."
Technical details
- Published
- 2019-03-13
Frequently asked questions
What is CVE-2019-9747?
In tinysvcmdns through 2018-01-16, a maliciously crafted mDNS (Multicast DNS) packet triggers an infinite loop while parsing an mDNS query. When mDNS compressed labels point to each other, the function uncompress_nlabel goes into an infinite loop trying to analyze the packet with an mDNS query. As a result, the mDNS server hangs after receiving the malicious mDNS packet. NOTE: the product's web site states "This project is un-maintained, and has been since 2013. ... There are known vulnerabilities ... You are advised to NOT use this library for any new projects / products."
Is CVE-2019-9747 actively exploited?
Active exploitation of CVE-2019-9747 has not been confirmed. Its EPSS score was 1.4% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2019-9747?
CVE-2019-9747 has a CVSS v3 base score of 7.5 (HIGH severity).
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