{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21647 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21647 is a high-severity memory corruption vulnerability in Linux kernel, published on 19 Jan 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-2025-21647 and fix it if it is affected.\n\nWhat it is: CVE-2025-21647 is a high-severity memory corruption vulnerability in Linux kernel, published on 19 Jan 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-2025-21647 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-2025-21647/ (Markdown: https://insights.sbomify.com/CVE-2025-21647/index.md)","id":"CVE-2025-21647","markdown":"https://insights.sbomify.com/CVE-2025-21647/index.md","name":"CVE-2025-21647","record":{"aliases":["BELL-CVE-2025-21647","DEBIAN-CVE-2025-21647","GHSA-j2g7-wj3p-j9c9","UBUNTU-CVE-2025-21647"],"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":"An out-of-bounds memory access in the Linux kernel's CAKE scheduler allows attackers to potentially execute code or cause a system crash.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.3,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","version":"3.1"},"cwes":[{"id":"CWE-125","name":"Out-of-bounds Read"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched: sch_cake: add bounds checks to host bulk flow fairness counts\n\nEven though we fixed a logic error in the commit cited below, syzbot\nstill managed to trigger an underflow of the per-host bulk flow\ncounters, leading to an out of bounds memory access.\n\nTo avoid any such logic errors causing out of bounds memory accesses,\nthis commit factors out all accesses to the per-host bulk flow counters\nto a series of helpers that perform bounds-checking before any\nincrements and decrements. This also has the benefit of improving\nreadability by moving the conditional checks for the flow mode into\nthese helpers, instead of having them spread out throughout the\ncode (which was the cause of the original logic error).\n\nAs part of this change, the flow quantum calculation is consolidated\ninto a helper function, which means that the dithering applied to the\nost load scaling is now applied both in the DRR rotation and when a\nsparse flow's quantum is first initiated. The only user-visible effect\nof this is that the maximum packet size that can be sent while a flow\nstays sparse will now vary with +/- one byte in some cases. This should\nnot make a noticeable difference in practice, and thus it's not worth\ncomplicating the code to preserve the old behaviour.","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":"sched: sch_cake: add bounds checks to host bulk flow fairness counts","id":"CVE-2025-21647","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"memory_corruption","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"netfilter: conntrack: clamp maximum hashtable size to INT_MAX","id":"CVE-2025-21648"},"packages":[],"prev":{"headline":"afs: Fix the maximum cell name length","id":"CVE-2025-21646"},"products":["Linux"],"published":"2025-01-19","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"An out-of-bounds memory access in the Linux kernel's CAKE scheduler allows attackers to potentially execute code or cause a system crash.","url":"https://insights.sbomify.com/CVE-2025-21647/"}