{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21823 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21823 is a high-severity use after free vulnerability in Linux kernel, published on 27 Feb 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-2025-21823 and fix it if it is affected.\n\nWhat it is: CVE-2025-21823 is a high-severity use after free vulnerability in Linux kernel, published on 27 Feb 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-2025-21823 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-2025-21823/ (Markdown: https://insights.sbomify.com/CVE-2025-21823/index.md)","id":"CVE-2025-21823","markdown":"https://insights.sbomify.com/CVE-2025-21823/index.md","name":"CVE-2025-21823","record":{"aliases":["BELL-CVE-2025-21823","DEBIAN-CVE-2025-21823","GHSA-cq4r-9fv8-53r2","ROOT-OS-UBUNTU-2404-CVE-2025-21823","UBUNTU-CVE-2025-21823"],"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","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel's batman-adv module allows attackers to cause memory corruption, 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":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: Drop unmanaged ELP metric worker\n\nThe ELP worker needs to calculate new metric values for all neighbors\n\"reachable\" over an interface. Some of the used metric sources require\nlocks which might need to sleep. This sleep is incompatible with the RCU\nlist iterator used for the recorded neighbors. The initial approach to work\naround of this problem was to queue another work item per neighbor and then\nrun this in a new context.\n\nEven when this solved the RCU vs might_sleep() conflict, it has a major\nproblems: Nothing was stopping the work item in case it is not needed\nanymore - for example because one of the related interfaces was removed or\nthe batman-adv module was unloaded - resulting in potential invalid memory\naccesses.\n\nDirectly canceling the metric worker also has various problems:\n\n* cancel_work_sync for a to-be-deactivated interface is called with\n  rtnl_lock held. But the code in the ELP metric worker also tries to use\n  rtnl_lock() - which will never return in this case. This also means that\n  cancel_work_sync would never return because it is waiting for the worker\n  to finish.\n* iterating over the neighbor list for the to-be-deactivated interface is\n  currently done using the RCU specific methods. Which means that it is\n  possible to miss items when iterating over it without the associated\n  spinlock - a behaviour which is acceptable for a periodic metric check\n  but not for a cleanup routine (which must \"stop\" all still running\n  workers)\n\nThe better approch is to get rid of the per interface neighbor metric\nworker and handle everything in the interface worker. The original problems\nare solved by:\n\n* creating a list of neighbors which require new metric information inside\n  the RCU protected context, gathering the metric according to the new list\n  outside the RCU protected context\n* only use rcu_trylock inside metric gathering code to avoid a deadlock\n  when the cancel_delayed_work_sync is called in the interface removal code\n  (which is called with the rtnl_lock held)","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":"batman-adv: Drop unmanaged ELP metric worker","id":"CVE-2025-21823","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":8,"next":{"headline":"gpu: host1x: Fix a use of uninitialized mutex","id":"CVE-2025-21824"},"packages":[],"prev":{"headline":"ptp: vmclock: Set driver data before its usage","id":"CVE-2025-21822"},"products":["Linux"],"published":"2025-02-27","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":"2026-08-05","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel's batman-adv module allows attackers to cause memory corruption, potentially leading to code execution or system crashes.","url":"https://insights.sbomify.com/CVE-2025-21823/"}