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Review reviewHigh

CVE-2021-47082

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: tun: avoid double free in tun_free_netdev Avoid double free in tun_free_netdev() by moving the dev->tstats and tun->security allocs to a new ndo_init routine (tun_net_init()) that will be called by register_netdevice(). ndo_init is paired with the desctructor (tun_free_netdev()), so if there's an error in register_netdevice() the destructor will handle the frees. BUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 CPU: 0 PID: 25750 Comm: syz-executor416 Not tainte...

CVSS
7.8
EPSS
0.25%
16.3% percentile
CISA KEV
Not listed
Published
2024.03.05
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.25%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: tun: avoid double free in tun_free_netdev Avoid double free in tun_free_netdev() by moving the dev->tstats and tun->security allocs to a new ndo_init routine (tun_net_init()) that will be called by register_netdevice(). ndo_init is paired with the desctructor (tun_free_netdev()), so if there's an error in register_netdevice() the destructor will handle the frees. BUG: KASAN: double-free or invalid-free in selinux_tun_dev_free_security+0x1a/0x20 security/selinux/hooks.c:5605 CPU: 0 PID: 25750 Comm: syz-executor416 Not tainte...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 662ca437e714caaab855b12415d6ffd815985bc0 < 8eb43d635950e27c29f1e9e49a23b31637f37757, >= 662ca437e714caaab855b12415d6ffd815985bc0 < 0c0e566f0387490d16f166808c72e9c772027681, >= 662ca437e714caaab855b12415d6ffd815985bc0 < a01a4e9f5dc93335c716fa4023b1901956e8c904, >= 662ca437e714caaab855b12415d6ffd815985bc0 < 3cb5ae77799e8ed6ec3fec0b6b4cd07f01650cc5, >= 662ca437e714caaab855b12415d6ffd815985bc0 < 158b515f703e75e7d68289bf4d98c664e1d632df, >= a81a02460bdf054ca0c60c5aed29941f7134092d, >= 6fc265f7a86d81e052508d03da555188f5882c3e, >= 3.10.16 < 3.11, >= 3.11.5 < 3.12, >= 3.12, < 4.19.280, >= 4.20 < 5.4.240, >= 5.5 < 5.10.136, >= 5.11 < 5.15.12, 5.16
Fixed versions
4.19.280, 5.4.240, 5.10.136, 5.15.12

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-415