What’s Vulnerable › Vulnerabilities

CVE-2021-3739

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-03-10 · updated 2026-09-01
• Weakness: CWE-476

Description

A NULL pointer dereference flaw was found in the btrfs_rm_device function in fs/btrfs/volumes.c in the Linux Kernel, where triggering the bug requires ‘CAP_SYS_ADMIN’. This flaw allows a local attacker to crash the system or leak kernel internal information. The highest threat from this vulnerability is to system availability.

Affected products

• Fedoraproject Fedora: 34
• Linux kernel: from 4.20 before 5.4.144; from 5.5 before 5.10.62; from 5.11 before 5.13.14; from 5.14 before 5.14.1 — fixed in 5.10.62, 5.13.14, 5.14.1, 5.4.144
• NetApp H300E Firmware: all versions
• NetApp H300S Firmware: all versions
• NetApp H410C Firmware: all versions
• NetApp H410S Firmware: all versions
• NetApp H500E Firmware: all versions
• NetApp H500S Firmware: all versions
• NetApp H700E Firmware: all versions
• NetApp H700S Firmware: all versions

How to fix

Upgrade to a fixed version: Linux kernel 5.10.62, 5.13.14, 5.14.1, 5.4.144. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1997958
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
• https://github.com/torvalds/linux/commit/e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
• https://security.netapp.com/advisory/ntap-20220407-0006/
• https://ubuntu.com/security/CVE-2021-3739
• https://www.openwall.com/lists/oss-security/2021/08/25/3
• https://bugzilla.redhat.com/show_bug.cgi?id=1997958
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
• https://github.com/torvalds/linux/commit/e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
• https://security.netapp.com/advisory/ntap-20220407-0006/
• https://ubuntu.com/security/CVE-2021-3739
• https://www.openwall.com/lists/oss-security/2021/08/25/3

Get alerted when CVE-2021-3739 or the next vulnerability affects your stack