#VU92051 Improper locking in Linux kernel - CVE-2021-46925

Vulnerability identifier: #VU92051

Vulnerability risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-46925

CWE-ID: CWE-667

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 improper locking within the smc_wr_is_tx_pend(), smc_wr_tx_process_cqe(), smc_wr_reg_send() and smc_wr_free_link() functions in net/smc/smc_wr.c, within the smc_ib_modify_qp_rts() function in net/smc/smc_ib.c, within the smc_conn_free(), smcr_link_clear(), smc_conn_kill(), smc_smcd_terminate_all(), smc_smcr_terminate_all(), smcr_link_down() and init_waitqueue_head() functions in net/smc/smc_core.c, within the smc_cdc_tx_handler(), smc_cdc_msg_send(), smcr_cdc_msg_send_validation() and smc_cdc_get_slot_and_msg_send() functions in net/smc/smc_cdc.c. A local user can perform a denial of service (DoS) attack.

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/e8a5988a85c719ce7205cb00dcf0716dcf611332
https://git.kernel.org/stable/c/b85f751d71ae8e2a15e9bda98852ea9af35282eb
https://git.kernel.org/stable/c/349d43127dac00c15231e8ffbcaabd70f7b0e544

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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.