#VU104497 Use-after-free in Linux kernel - CVE-2021-47656

Vulnerability identifier: #VU104497

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-47656

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the jffs2_free_ino_caches() function in fs/jffs2/fs.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

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External links
https://git.kernel.org/stable/c/22327bd7988f21de3a53c1373f3b81542bfe1f44
https://git.kernel.org/stable/c/30bf7244acf32f19cb722c39f7bc1c2a9f300422
https://git.kernel.org/stable/c/3bd2454162ec6bbb5503233c804fce6e4b6dcec5
https://git.kernel.org/stable/c/4c7c44ee1650677fbe89d86edbad9497b7679b5c
https://git.kernel.org/stable/c/7a75740206af5f17e9f3efa384211cba70213da1
https://git.kernel.org/stable/c/7bb7428dd73991bf4b3a7a61b493ca50046c2b13
https://git.kernel.org/stable/c/8c0f024f29e055840a5a89fe23b96ae3f921afed
https://git.kernel.org/stable/c/9150cb625b46f68d524f4cfd491f1aafc23e10a9
https://git.kernel.org/stable/c/c3b07c875fa8f906f932976460fd14798596f101

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.