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CVE-2021-39923

NULL pointer exception in the IPPUSB dissector in Wireshark 3.4.0 to 3.4.9 allows denial of...

7.5 HighFix available

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

1.61%Up 0.6 points since Nov 20, 2021
90%50%10%1%

What each source reports

CVE List Score used7.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
CVE-2021-39923
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
EUVDEUVD-2021-262797.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
EUVD-2021-26279
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-v75m-35ph-56m27.5

NULL pointer exception in the IPPUSB dissector in Wireshark 3.4.0 to 3.4.9 allows denial of...

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

Record
GHSA-v75m-35ph-56m2
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-476, CWE-834
Updated
2026-11-02
NVD7.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
CVE-2021-39923
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-834
Updated
2026-11-02
OSVAZL-74117.5

CVE-2021-39923 affecting package wireshark for versions less than 3.4.14-1

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
AZL-7411
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSV7.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
CVE-2021-39923
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-399237.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
DEBIAN-CVE-2021-39923
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-399237.5

Large loop in the PNRP dissector in Wireshark 3.4.0 to 3.4.9 and 3.2.0 to 3.2.17 allows denial of service via packet injection or crafted capture file

Record
UBUNTU-CVE-2021-39923
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
wireshark
Azure Linux:2
before 3.4.14-1
3.4.14-1
wireshark
Debian:12
before 3.6.0-1
3.6.0-1
wireshark
Debian:13
before 3.6.0-1
3.6.0-1
wireshark
Debian:14
before 3.6.0-1
3.6.0-1
wireshark
Debian:9
From an advisory covering 9 CVEs
before 2.6.20-0+deb9u2, plus listed versions
2.2.6+g32dac6a-22.2.6+g32dac6a-2+deb9u12.2.6+g32dac6a-2+deb9u22.2.6+g32dac6a-2+deb9u32.2.7-1
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2.4.0-12.4.1-12.4.2-12.4.3-12.4.4-12.4.5-12.4.6-12.6.1-12.6.10-12.6.2-12.6.2-22.6.20-0+deb9u12.6.3-12.6.3-1~deb9u12.6.4-12.6.4-22.6.5-12.6.5-1~deb9u12.6.6-12.6.7-12.6.7-1~deb9u12.6.8-12.6.8-1.12.6.8-1.1~deb9u12.6.9-1
2.6.20-0+deb9u2
wireshark
Debian:11
From an advisory covering 12 CVEs
before 3.4.10-0+deb11u1, plus listed versions
3.4.4-13.4.6-1~exp13.4.7-13.4.7-1~exp13.4.8-13.4.9-1
3.4.10-0+deb11u1
wireshark
Ubuntu:Pro:14.04:LTS
All versions, plus listed versions
1.10.2-11.10.3-11.10.5-1ubuntu11.10.5-21.10.6-1
Show 9 moreShow less
1.12.1+g01b65bf-4+deb8u11ubuntu0.14.04.12.6.3-1~ubuntu14.04.12.6.4-2~ubuntu14.04.12.6.5-1~ubuntu14.04.12.6.6-1~ubuntu14.04.02.6.8-1~ubuntu14.04.0~esm12.6.10-1~ubuntu14.04.0~esm12.6.10-1~ubuntu14.04.0~esm22.6.10-1~ubuntu14.04.0~esm3
None known
wireshark
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
1.12.7+g7fc8978-11.12.8+g5b6e543-22.0.1+g59ea380-3build12.0.2+ga16e22e-12.2.6+g32dac6a-2ubuntu0.16.04
Show 8 moreShow less
2.6.3-1~ubuntu16.04.12.6.4-2~ubuntu16.04.02.6.5-1~ubuntu16.04.02.6.6-1~ubuntu16.04.02.6.8-1~ubuntu16.04.02.6.10-1~ubuntu16.04.02.6.10-1~ubuntu16.04.0+esm12.6.10-1~ubuntu16.04.0+esm2
None known
wireshark
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
2.4.2-12.4.3-12.4.4-12.4.5-12.6.3-1~ubuntu18.04.1
Show 7 moreShow less
2.6.4-2~ubuntu18.04.02.6.5-1~ubuntu18.04.02.6.6-1~ubuntu18.04.02.6.8-1~ubuntu18.04.02.6.10-1~ubuntu18.04.02.6.10-1~ubuntu18.04.0+esm12.6.10-1~ubuntu18.04.0+esm2
None known
wireshark
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
3.0.5-13.0.7-13.2.1-13.2.2-13.2.3-13.2.3-1ubuntu0.1~esm13.2.3-1ubuntu0.1~esm2
None known
wireshark
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
3.4.7-1~exp13.4.9-13.6.2-1ubuntu13.6.2-23.6.2-2ubuntu0.1~esm1
None known

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-39923 is a high vulnerability (CVSS 7.5) in Wireshark, published November 19, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.61%, the 76th percentile. Fixed in wireshark 3.4.14-1.

References

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