CVE-2025-21805: Linux Kernel vulnerability (CVSS 9.8)

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Linux Kernel≥ 6.12 < 6.12.13 · ≥ 6.13 < 6.13.2

Remediation

Fixed in

Linux Kernel≥ 6.12.13

Patch & vendor advisories

References

Frequently asked

Is CVE-2025-21805 being actively exploited?

CVE-2025-21805 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.39%.

How severe is CVE-2025-21805?

CVE-2025-21805 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.39% probability of exploitation.

Which products are affected by CVE-2025-21805?

Affected products include Linux Kernel.

How do I fix CVE-2025-21805?

Upgrade affected software to a fixed version, for example Linux Kernel 6.12.13 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-21805 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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