#VU91409 Infinite loop in Linux kernel - CVE-2021-47448

Vulnerability identifier: #VU91409

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-47448

CWE-ID: CWE-835

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 perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop within the mptcp_check_data_fin(), mptcp_data_ready(), mptcp_check_for_eof(), mptcp_wait_data(), mptcp_recvmsg(), tcp_recv_timestamp(), mptcp_check_fastclose(), mptcp_check_readable() and mptcp_poll() functions in net/mptcp/protocol.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.14, 5.14 rc1, 5.14 rc2, 5.14 rc3, 5.14 rc4, 5.14 rc7, 5.14.0-49.el9, 5.14.1, 5.14.2, 5.14.3, 5.14.4, 5.14.5, 5.14.6, 5.14.7, 5.14.8, 5.14.9, 5.14.10, 5.14.11, 5.14.12, 5.14.13, 5.15 rc1, 5.15 rc2, 5.15 rc3, 5.15 rc4, 5.15 rc5, 5.15 rc6, 5.15 rc7

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External links
https://git.kernel.org/stable/c/1a4554e94f0deff9fc1dc5addf93fa579cc29711
https://git.kernel.org/stable/c/612f71d7328c14369924384ad2170aae2a6abd92
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.14
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15

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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.