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CVE-2021-47237

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: net: hamradio: fix memory leak in mkiss_close My local syzbot instance hit memory leak in mkiss_open()[1].

Published May 21, 2024CWE-401EPSS 0.23%

Overview

CVE-2021-47237 is a medium-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: hamradio: fix memory leak in mkiss_close

My local syzbot instance hit memory leak in

mkiss_open()[1]. The problem was in missing

free_netdev() in mkiss_close().

In mkiss_open() netdevice is allocated and then

registered, but in mkiss_close() netdevice was

only unregistered, but not freed.

Fail log:

BUG: memory leak

unreferenced object 0xffff8880281ba000 (size 4096):

comm "syz-executor.1", pid 11443, jiffies 4295046091 (age 17.660s)

hex dump (first 32 bytes):

61 78 30 00 00 00 00 00 00 00 00 00 00 00 00 00 ax0.............

00 27 fa 2a 80 88 ff ff 00 00 00 00 00 00 00 00 .'.*............

backtrace:

[<ffffffff81a27201>] kvmalloc_node+0x61/0xf0

[<ffffffff8706e7e8>] alloc_netdev_mqs+0x98/0xe80

[<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1]

[<ffffffff842355db>] tty_ldisc_open+0x9b/0x110

[<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670

[<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/290b0b6432e2599021db0b8d6046f756d931c29fRefgit.kernel.org/stable/c/3942d0f9ace1a95a74930b5b4fc0e5005c62b37bRefgit.kernel.org/stable/c/765a8a04f828db7222b36a42b1031f576bfe95c3Refgit.kernel.org/stable/c/7edcc682301492380fbdd604b4516af5ae667a13Refgit.kernel.org/stable/c/a49cbb762ef20655f5c91abdc13658b0af5e159dRefgit.kernel.org/stable/c/c16c4716a1b5ba4f83c7e00da457cba06761f119Refgit.kernel.org/stable/c/c634ba0b4159838ff45a60d3a0ace3b4118077a5Refgit.kernel.org/stable/c/f4de2b43d13b7cf3ced9310e371b90c836dbd7cdRefgit.kernel.org/stable/c/290b0b6432e2599021db0b8d6046f756d931c29fRefgit.kernel.org/stable/c/3942d0f9ace1a95a74930b5b4fc0e5005c62b37b

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47237?

CVE-2021-47237 is a medium-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47237?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47237?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47237?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47237 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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