CVE-2021-39926 Memory corruption in Wireshark

What is CVE-2021-39926?

CVE-2021-39926 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 19 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Buffer overflow in the Bluetooth HCI_ISO dissector in Wireshark 3.4.0 to 3.4.9 allows denial of service via packet injection or crafted capture file

Weakness: CWE-120

Which versions are affected by CVE-2021-39926?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Wireshark Wireshark.

How do I fix CVE-2021-39926?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-39926 being exploited?

There is no known exploitation of CVE-2021-39926 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-7414, DEBIAN-CVE-2021-39926, GHSA-g42c-hpcx-483f, UBUNTU-CVE-2021-39926.