CVE-2021-39920: Wireshark NULL Pointer Dereference (CVSS 7.5)
CVE-2021-39920 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. NULL pointer exception in the IPPUSB dissector in Wireshark 3.4.0 to 3.4.9 allows denial of service via packet injection or crafted capture file. EPSS estimates a 3.16% chance of exploitation in the next 30 days.
Description
NULL pointer exception in the IPPUSB dissector in Wireshark 3.4.0 to 3.4.9 allows denial of service via packet injection or crafted capture file
Metrics
CVSS 3.17.5/10 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Probability 3.16%
86.3th percentile
Probability of exploitation in the next 30 days. Learn more
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Wireshark | Wireshark | >= 3.4.0, < 3.4.10 |
| Fedoraproject | Fedora | 34 |
| Fedoraproject | Fedora | 35 |
References
- Third Party Advisory
- Exploit, Issue Tracking, Third Party Advisory
- Third Party Advisory
- Third Party Advisory
- Third Party Advisory
- Third Party Advisory
- Vendor Advisory
Timeline
Published Nov 18, 2021 Last Modified Jun 17, 2026 Status Modified
Frequently Asked Questions
What is CVE-2021-39920?
NULL pointer exception in the IPPUSB dissector in Wireshark 3.4.0 to 3.4.9 allows denial of service via packet injection or crafted capture file
How severe is CVE-2021-39920?
CVE-2021-39920 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 3.16% probability of exploitation in the next 30 days.
How do I fix CVE-2021-39920?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.