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Vulnerability · Published Nov 19, 2021 · Assigned by GitLab

CVE-2021-39921

High 7.5

In plain English

A high-severity security flaw in Wireshark from Wireshark Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 3.4% (higher than 89% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)3.4%top 11.2% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

NULL pointer exception in the Modbus 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

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20wireshark3.4.11-r0ALPINE-CVE-2021-39921
Alpine:v3.21wireshark3.4.11-r0ALPINE-CVE-2021-39921
Alpine:v3.22wireshark3.4.11-r0ALPINE-CVE-2021-39921
Alpine:v3.23wireshark3.4.11-r0ALPINE-CVE-2021-39921
Alpine:v3.24wireshark3.4.11-r0ALPINE-CVE-2021-39921
Debian:12wireshark3.6.0-1DEBIAN-CVE-2021-39921
Debian:13wireshark3.6.0-1DEBIAN-CVE-2021-39921
Debian:14wireshark3.6.0-1DEBIAN-CVE-2021-39921
Ubuntu:24.04:LTSwiresharkno fix listedUBUNTU-CVE-2021-39921
Ubuntu:25.10wiresharkno fix listedUBUNTU-CVE-2021-39921
Ubuntu:26.04:LTSwiresharkno fix listedUBUNTU-CVE-2021-39921
Ubuntu:26.10wiresharkno fix listedUBUNTU-CVE-2021-39921

Affected products (as reported)

VendorProductVersions
Wireshark Foundation Wireshark >=3.4.0, <3.4.10>=3.2.0, <3.2.18

References