How severe is CVE-2021-39920?

CVE-2021-39920 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-39920 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39920?

CVE-2021-39920 primarily affects Wireshark. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39920?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39920 published?

CVE-2021-39920 was published on 2021-11-18 and last updated on 2026-06-17.

CVE-2021-39920

CVE-2021-39920 is a high-severity vulnerability in Wireshark with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Wireshark
Published: 2021-11-18
Last modified: 2026-06-17

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

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 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-39920 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39920?: CVE-2021-39920 primarily affects Wireshark. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39920?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39920 published?: CVE-2021-39920 was published on 2021-11-18 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:wireshark:wireshark:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

More vulnerabilities in Wireshark

CVE-2011-0444 — Critical (CVSS 10.0): Buffer overflow in the MAC-LTE dissector (epan/dissectors/packet-mac-lte.c) in Wireshark 1.2.0 through 1.2.13 and 1.4.0…
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CVE-2010-2994 — Critical (CVSS 10.0): Stack-based buffer overflow in the ASN.1 BER dissector in Wireshark 0.10.13 through 1.0.14 and 1.2.0 through 1.2.9 has…
CVE-2009-1266 — Critical (CVSS 10.0): Unspecified vulnerability in Wireshark before 1.0.7 has unknown impact and attack vectors.
CVE-2009-1210 — Critical (CVSS 10.0): Format string vulnerability in the PROFINET/DCP (PN-DCP) dissector in Wireshark 1.0.6 and earlier allows remote…
CVE-2008-3146 — Critical (CVSS 10.0): Multiple buffer overflows in packet_ncp2222.inc in Wireshark (formerly Ethereal) 0.9.7 through 1.0.2 allow attackers to…

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