{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21887 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21887 is a high-severity use after free 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-2025-21887 and fix it if it is affected.\n\nWhat it is: CVE-2025-21887 is a high-severity use after free 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-2025-21887 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-2025-21887/ (Markdown: https://insights.sbomify.com/CVE-2025-21887/index.md)","id":"CVE-2025-21887","markdown":"https://insights.sbomify.com/CVE-2025-21887/index.md","name":"CVE-2025-21887","record":{"aliases":["AZL-59405","BELL-CVE-2025-21887","DEBIAN-CVE-2025-21887","GHSA-vjwm-w9rc-f4cc","ROOT-OS-DEBIAN-11-CVE-2025-21887","ROOT-OS-UBUNTU-2404-CVE-2025-21887","UBUNTU-CVE-2025-21887"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel's overlayfs allows local attackers to potentially execute arbitrary code or escalate privileges.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\novl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up\n\nThe issue was caused by dput(upper) being called before\novl_dentry_update_reval(), while upper-\u003ed_flags was still\naccessed in ovl_dentry_remote().\n\nMove dput(upper) after its last use to prevent use-after-free.\n\nBUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\nBUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0xc3/0x620 mm/kasan/report.c:488\n kasan_report+0xd9/0x110 mm/kasan/report.c:601\n ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\n ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n ovl_link_up fs/overlayfs/copy_up.c:610 [inline]\n ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170\n ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223\n ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136\n vfs_rename+0xf84/0x20a0 fs/namei.c:4893\n...\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":"ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up","id":"CVE-2025-21887","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"RDMA/mlx5: Fix a WARN during dereg_mr for DM type","id":"CVE-2025-21888"},"packages":[],"prev":{"headline":"RDMA/mlx5: Fix implicit ODP hang on parent deregistration","id":"CVE-2025-21886"},"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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel's overlayfs allows local attackers to potentially execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2025-21887/"}