CVE-2025-21805: linux kernel vulnerability

CVE-2025-21805: critical vulnerability affecting linux kernel. Check CVSS, KEV status, business impact and recommended administrator actions.
CVE-2025-21805CVSS 9.8Linux

CVE-2025-21805: linux kernel vulnerability

CVE-2025-21805: critical vulnerability affecting linux kernel. Check CVSS, KEV status, business impact and recommended administrator actions.

CVSS
9.8 CRITICAL
EPSS
31.98%
Known exploited
not in KEV
Product
linux kernel

What is known

In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs: Add missing deinit() call A warning is triggered when repeatedly connecting and disconnecting the rnbd: list_add corruption. prev->next should be next (ffff88800b13e480), but was ffff88801ecd1338. (prev=ffff88801ecd1340). WARNING: CPU: 1 PID: 36562 at lib/list_debug.c:32 __list_add_valid_or_report+0x7f/0xa0 Workqueue: ib_cm cm_work_handler [ib_cm] RIP: 0010:__list_add_valid_or_report+0x7f/0xa0 ? __list_add_valid_or_report+0x7f/0xa0 ib_register_event_handler+0x65/0x93 [ib_core] rtrs_srv_ib_dev_init+0x29/0x30 [rtrs_server] rtrs_ib_dev_find_or_add+0x124/0x1d0 [rtrs_core] __alloc_path+0x46c/0x680 [rtrs_server] ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server] ? rcu_is_watching+0xd/0x40 ? __mutex_lock+0x312/0xcf0 ? get_or_create_srv+0xad/0x310 [rtrs_server] ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server] rtrs_rdma_connect+0x23c/0x2d0 [rtrs_server] ? __lock_release+0x1b1/0x2d0 cma_cm_event_handler+0x4a/0x1a0 [rdma_cm] cma_ib_req_handler+0x3a0/0x7e0 [rdma_cm] cm_process_work+0x28/0x1a0 [ib_cm] ? _raw_spin_unlock_irq+0x2f/0x50 cm_req_handler+0x618/0xa60 [ib_cm] cm_work_handler+0x71/0x520 [ib_cm] Commit 667db86bcbe8 ("RDMA/rtrs: Register ib event handler") introduced a new element .deinit but never used it at all. Fix it by invoking the `deinit()` to appropriately unregister the IB event handler.

Business impact

Successful exploitation of CVE-2025-21805, a critical vulnerability (CVSS 9.8) affecting linux kernel, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether linux kernel is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

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