{"cve":"CVE-2025-21886","nvd":{"published":"2025-03-27T15:15:56.510","modified":"2026-10-21T13:18:02.590","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix implicit ODP hang on parent deregistration\n\nFix the destroy_unused_implicit_child_mr() to prevent hanging during\nparent deregistration as of below [1].\n\nUpon entering destroy_unused_implicit_child_mr(), the reference count\nfor the implicit MR parent is incremented using:\nrefcount_inc_not_zero().\n\nA corresponding decrement must be performed if\nfree_implicit_child_mr_work() is not called.\n\nThe code has been updated to properly manage the reference count that\nwas incremented.\n\n[1]\nINFO: task python3:2157 blocked for more than 120 seconds.\nNot tainted 6.12.0-rc7+ #1633\n\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\ntask:python3         state:D stack:0     pid:2157 tgid:2157  ppid:1685   flags:0x00000000\nCall Trace:\n<TASK>\n__schedule+0x420/0xd30\nschedule+0x47/0x130\n__mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib]\n? __pfx_autoremove_wake_function+0x10/0x10\nib_dereg_mr_user+0x5f/0x120 [ib_core]\n? lock_release+0xc6/0x280\ndestroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs]\nuverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs]\nuobj_destroy+0x3f/0x70 [ib_uverbs]\nib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs]\n? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs]\n? lock_acquire+0xc1/0x2f0\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs]\n? lock_release+0xc6/0x280\nib_uverbs_ioctl+0xe7/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n __x64_sys_ioctl+0x1b0/0xa70\n? kmem_cache_free+0x221/0x400\ndo_syscall_64+0x6b/0x140\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7f20f21f017b\nRSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b\nRDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003\nRBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60\nR10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890\nR13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0\n</TASK>","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/3d8c6f26893d55fab218ad086719de1fc9bb86ba","https://git.kernel.org/stable/c/a095ede2daca49d15e74d66d014883f2fa8bb924","https://git.kernel.org/stable/c/cb96ae783e7249e8e5a50c22952c0bb2983133df"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2025-21886","score":0.00241,"percentile":0.15093,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}