PatchTheCVECVE-2019-9747: In tinysvcmdns through 2018-01-16, a maliciously crafted mDNS (Multicast DNS) packet triggers an infinite loop
CVE-2019-9747 is a high-severity flaw (CVSS 7.5) affecting tinysvcmdns. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- High severity
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.4% (top 28%) |
| CISA exploited list | No |
| Weakness | CWE-835 |
| Published | 2019-03-13 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2019-9747?
tinysvcmdns: upgrade to newer than 2018-01-16. Exact commands for each OS are on this page.
Is CVE-2019-9747 being exploited?
CVE-2019-9747 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2019-9747 affect?
CVE-2019-9747 affects tinysvcmdns. Severity is high (CVSS 7.5). 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 infinit
How urgent is CVE-2019-9747?
Priority 54/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2019-9748 CRITICAL 9.1 UPGRADE In tinysvcmdns through 2018-01-16, an mDNS server processing a crafted packet can perform arbitrary data read
- CVE-2017-12130 HIGH 7.5 DOWNGRADE An exploitable NULL pointer dereference vulnerability exists in the tinysvcmdns library version 2017-11-05
- CVE-2017-12087 CRITICAL 10.0 DOWNGRADE An exploitable heap overflow vulnerability exists in the tinysvcmdns library version 2016-07-18