{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21899 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21899 is a high-severity use after free vulnerability in Linux kernel, published on 1 Apr 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-2025-21899 and fix it if it is affected.\n\nWhat it is: CVE-2025-21899 is a high-severity use after free vulnerability in Linux kernel, published on 1 Apr 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-2025-21899 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-2025-21899/ (Markdown: https://insights.sbomify.com/CVE-2025-21899/index.md)","id":"CVE-2025-21899","markdown":"https://insights.sbomify.com/CVE-2025-21899/index.md","name":"CVE-2025-21899","record":{"aliases":["AZL-69527","BELL-CVE-2025-21899","DEBIAN-CVE-2025-21899","GHSA-vp9f-g82m-h958","ROOT-OS-DEBIAN-11-CVE-2025-21899","ROOT-OS-UBUNTU-2204-CVE-2025-21899","ROOT-OS-UBUNTU-2404-CVE-2025-21899","UBUNTU-CVE-2025-21899"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free bug in the Linux kernel tracing subsystem allows local attackers to cause a system crash by corrupting the named triggers list.","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-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix bad hist from corrupting named_triggers list\n\nThe following commands causes a crash:\n\n ~# cd /sys/kernel/tracing/events/rcu/rcu_callback\n ~# echo 'hist:name=bad:keys=common_pid:onmax(bogus).save(common_pid)' \u003e trigger\n bash: echo: write error: Invalid argument\n ~# echo 'hist:name=bad:keys=common_pid' \u003e trigger\n\nBecause the following occurs:\n\nevent_trigger_write() {\n  trigger_process_regex() {\n    event_hist_trigger_parse() {\n\n      data = event_trigger_alloc(..);\n\n      event_trigger_register(.., data) {\n        cmd_ops-\u003ereg(.., data, ..) [hist_register_trigger()] {\n          data-\u003eops-\u003einit() [event_hist_trigger_init()] {\n            save_named_trigger(name, data) {\n              list_add(\u0026data-\u003enamed_list, \u0026named_triggers);\n            }\n          }\n        }\n      }\n\n      ret = create_actions(); (return -EINVAL)\n      if (ret)\n        goto out_unreg;\n[..]\n      ret = hist_trigger_enable(data, ...) {\n        list_add_tail_rcu(\u0026data-\u003elist, \u0026file-\u003etriggers); \u003c\u003c\u003c---- SKIPPED!!! (this is important!)\n[..]\n out_unreg:\n      event_hist_unregister(.., data) {\n        cmd_ops-\u003eunreg(.., data, ..) [hist_unregister_trigger()] {\n          list_for_each_entry(iter, \u0026file-\u003etriggers, list) {\n            if (!hist_trigger_match(data, iter, named_data, false))   \u003c- never matches\n                continue;\n            [..]\n            test = iter;\n          }\n          if (test \u0026\u0026 test-\u003eops-\u003efree) \u003c\u003c\u003c-- test is NULL\n\n            test-\u003eops-\u003efree(test) [event_hist_trigger_free()] {\n              [..]\n              if (data-\u003ename)\n                del_named_trigger(data) {\n                  list_del(\u0026data-\u003enamed_list);  \u003c\u003c\u003c\u003c-- NEVER gets removed!\n                }\n              }\n           }\n         }\n\n         [..]\n         kfree(data); \u003c\u003c\u003c-- frees item but it is still on list\n\nThe next time a hist with name is registered, it causes an u-a-f bug and\nthe kernel can crash.\n\nMove the code around such that if event_trigger_register() succeeds, the\nnext thing called is hist_trigger_enable() which adds it to the list.\n\nA bunch of actions is called if get_named_trigger_data() returns false.\nBut that doesn't need to be called after event_trigger_register(), so it\ncan be moved up, allowing event_trigger_register() to be called just\nbefore hist_trigger_enable() keeping them together and allowing the\nfile-\u003etriggers to be properly populated.","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":"tracing: Fix bad hist from corrupting named_triggers list","id":"CVE-2025-21899","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":5,"next":{"headline":"NFSv4: Fix a deadlock when recovering state on a sillyrenamed file","id":"CVE-2025-21900"},"packages":[],"prev":{"headline":"ftrace: Avoid potential division by zero in function_stat_show()","id":"CVE-2025-21898"},"products":["Linux"],"published":"2025-04-01","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 bug in the Linux kernel tracing subsystem allows local attackers to cause a system crash by corrupting the named triggers list.","url":"https://insights.sbomify.com/CVE-2025-21899/"}