{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21886 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21886 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-21886 and fix it if it is affected.\n\nWhat it is: CVE-2025-21886 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-21886 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-21886/ (Markdown: https://insights.sbomify.com/CVE-2025-21886/index.md)","id":"CVE-2025-21886","markdown":"https://insights.sbomify.com/CVE-2025-21886/index.md","name":"CVE-2025-21886","record":{"aliases":["BELL-CVE-2025-21886","DEBIAN-CVE-2025-21886","GHSA-4q32-287f-wf74","UBUNTU-CVE-2025-21886"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel RDMA driver","requires_auth":"low_privilege","summary":"A reference counting bug in the Linux kernel's mlx5 RDMA driver causes a system hang during memory deregistration, leading to denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"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 \u003e /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\u003cTASK\u003e\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\u003c/TASK\u003e","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"RDMA/mlx5: Fix implicit ODP hang on parent deregistration","id":"CVE-2025-21886","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up","id":"CVE-2025-21887"},"packages":[],"prev":{"headline":"RDMA/bnxt_re: Fix the page details for the srq created by kernel consumers","id":"CVE-2025-21885"},"products":["Linux"],"published":"2025-03-27","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"A reference counting bug in the Linux kernel's mlx5 RDMA driver causes a system hang during memory deregistration, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2025-21886/"}