Security assessments indicate that CVE-2025-21886 presents a notable risk, potentially requiring prompt mitigation.
Status: Analyzed
Last updated: 🕟 29 Oct 2025, 16:53 UTC
Originally published on: 🕒 27 Mar 2025, 15:15 UTC
Time between publication and last update: 216 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVE-2025-21886: In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix implicit ODP hang on parent deregistration Fix the destroy_unused_implicit_child_mr() to prevent hanging during parent deregistration as of below [1]. Upon entering destroy_unused_implicit_child_mr(), the reference count for the implicit MR parent is incremented using: refcount_inc_not_zero(). A corresponding decrement must be performed if free_implicit_child_mr_work() is not called. The code has been updated to properly manage the reference count that was incremented. [1] INFO: task python3:2157 blocked for more than 120 seconds. Not tainted 6.12.0-rc7+ #1633 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:python3 state:D stack:0 pid:2157 tgid:2157 ppid:1685 flags:0x00000000 Call Trace: <TASK> __schedule+0x420/0xd30 schedule+0x47/0x130 __mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib] ? __pfx_autoremove_wake_function+0x10/0x10 ib_dereg_mr_user+0x5f/0x120 [ib_core] ? lock_release+0xc6/0x280 destroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs] uverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs] uobj_destroy+0x3f/0x70 [ib_uverbs] ib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs] ? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs] ? lock_acquire+0xc1/0x2f0 ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] ? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs] ? lock_release+0xc6/0x280 ib_uverbs_ioctl+0xe7/0x170 [ib_uverbs] ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] __x64_sys_ioctl+0x1b0/0xa70 ? kmem_cache_free+0x221/0x400 do_syscall_64+0x6b/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f20f21f017b RSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b RDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003 RBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60 R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890 R13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0 </TASK>
The exploitability of CVE-2025-21886 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2025-21886 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2025-21886, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2025-21886, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
NVD-CWE-Other
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