{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-39863 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-39863 is a high-severity use after free vulnerability in Linux kernel, published on 19 Sep 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-2025-39863 and fix it if it is affected.\n\nWhat it is: CVE-2025-39863 is a high-severity use after free vulnerability in Linux kernel, published on 19 Sep 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-2025-39863 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-2025-39863/ (Markdown: https://insights.sbomify.com/CVE-2025-39863/index.md)","id":"CVE-2025-39863","markdown":"https://insights.sbomify.com/CVE-2025-39863/index.md","name":"CVE-2025-39863","record":{"aliases":["AZL-67563","AZL-72349","BELL-CVE-2025-39863","DEBIAN-CVE-2025-39863","GHSA-c7cr-ch33-3xr3","ROOT-OS-DEBIAN-11-CVE-2025-39863","ROOT-OS-DEBIAN-12-CVE-2025-39863","ROOT-OS-DEBIAN-13-CVE-2025-39863","ROOT-OS-UBUNTU-2204-CVE-2025-39863","ROOT-OS-UBUNTU-2404-CVE-2025-39863","UBUNTU-CVE-2025-39863"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel driver","requires_auth":"low_privilege","summary":"A race condition in the Linux kernel's brcmfmac Wi-Fi driver allows attackers to trigger a use-after-free, potentially leading to code execution or system crashes.","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\nwifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work\n\nThe brcmf_btcoex_detach() only shuts down the btcoex timer, if the\nflag timer_on is false. However, the brcmf_btcoex_timerfunc(), which\nruns as timer handler, sets timer_on to false. This creates critical\nrace conditions:\n\n1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc()\nis executing, it may observe timer_on as false and skip the call to\ntimer_shutdown_sync().\n\n2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info\nworker after the cancel_work_sync() has been executed, resulting in\nuse-after-free bugs.\n\nThe use-after-free bugs occur in two distinct scenarios, depending on\nthe timing of when the brcmf_btcoex_info struct is freed relative to\nthe execution of its worker thread.\n\nScenario 1: Freed before the worker is scheduled\n\nThe brcmf_btcoex_info is deallocated before the worker is scheduled.\nA race condition can occur when schedule_work(\u0026bt_local-\u003ework) is\ncalled after the target memory has been freed. The sequence of events\nis detailed below:\n\nCPU0                           | CPU1\nbrcmf_btcoex_detach            | brcmf_btcoex_timerfunc\n                               |   bt_local-\u003etimer_on = false;\n  if (cfg-\u003ebtcoex-\u003etimer_on)   |\n    ...                        |\n  cancel_work_sync();          |\n  ...                          |\n  kfree(cfg-\u003ebtcoex); // FREE  |\n                               |   schedule_work(\u0026bt_local-\u003ework); // USE\n\nScenario 2: Freed after the worker is scheduled\n\nThe brcmf_btcoex_info is freed after the worker has been scheduled\nbut before or during its execution. In this case, statements within\nthe brcmf_btcoex_handler() — such as the container_of macro and\nsubsequent dereferences of the brcmf_btcoex_info object will cause\na use-after-free access. The following timeline illustrates this\nscenario:\n\nCPU0                            | CPU1\nbrcmf_btcoex_detach             | brcmf_btcoex_timerfunc\n                                |   bt_local-\u003etimer_on = false;\n  if (cfg-\u003ebtcoex-\u003etimer_on)    |\n    ...                         |\n  cancel_work_sync();           |\n  ...                           |   schedule_work(); // Reschedule\n                                |\n  kfree(cfg-\u003ebtcoex); // FREE   |   brcmf_btcoex_handler() // Worker\n  /*                            |     btci = container_of(....); // USE\n   The kfree() above could      |     ...\n   also occur at any point      |     btci-\u003e // USE\n   during the worker's execution|\n   */                           |\n\nTo resolve the race conditions, drop the conditional check and call\ntimer_shutdown_sync() directly. It can deactivate the timer reliably,\nregardless of its current state. Once stopped, the timer_on state is\nthen set to false.","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":"wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work","id":"CVE-2025-39863","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":6,"next":{"headline":"wifi: cfg80211: fix use-after-free in cmp_bss()","id":"CVE-2025-39864"},"packages":[],"prev":{"headline":"wifi: mt76: mt7915: fix list corruption after hardware restart","id":"CVE-2025-39862"},"products":["Linux"],"published":"2025-09-19","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 race condition in the Linux kernel's brcmfmac Wi-Fi driver allows attackers to trigger a use-after-free, potentially leading to code execution or system crashes.","url":"https://insights.sbomify.com/CVE-2025-39863/"}