{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40008 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40008 is a memory corruption vulnerability in Linux, published on 20 Oct 2025."},"fix_prompt":"Check this codebase for CVE-2025-40008 and fix it if it is affected.\n\nWhat it is: CVE-2025-40008 is a memory corruption vulnerability in Linux, published on 20 Oct 2025. \nExploitation: There is no known exploitation of CVE-2025-40008 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2025-40008/ (Markdown: https://insights.sbomify.com/CVE-2025-40008/index.md)","id":"CVE-2025-40008","markdown":"https://insights.sbomify.com/CVE-2025-40008/index.md","name":"CVE-2025-40008","record":{"aliases":["BELL-CVE-2025-40008","DEBIAN-CVE-2025-40008","GHSA-jv2g-f3mc-8f2c","ROOT-OS-DEBIAN-12-CVE-2025-40008","ROOT-OS-DEBIAN-13-CVE-2025-40008","ROOT-OS-UBUNTU-2404-CVE-2025-40008","UBUNTU-CVE-2025-40008"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"unknown","non_default_config":true,"product_category":"Linux kernel","requires_auth":"none","summary":"A bug in KMSAN shadow memory handling causes a kernel crash when processing unaligned buffers near guard pages, requiring a patched kernel.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nkmsan: fix out-of-bounds access to shadow memory\n\nRunning sha224_kunit on a KMSAN-enabled kernel results in a crash in\nkmsan_internal_set_shadow_origin():\n\n    BUG: unable to handle page fault for address: ffffbc3840291000\n    #PF: supervisor read access in kernel mode\n    #PF: error_code(0x0000) - not-present page\n    PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0\n    Oops: 0000 [#1] SMP NOPTI\n    CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G                 N  6.17.0-rc3 #10 PREEMPT(voluntary)\n    Tainted: [N]=TEST\n    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n    RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100\n    [...]\n    Call Trace:\n    \u003cTASK\u003e\n    __msan_memset+0xee/0x1a0\n    sha224_final+0x9e/0x350\n    test_hash_buffer_overruns+0x46f/0x5f0\n    ? kmsan_get_shadow_origin_ptr+0x46/0xa0\n    ? __pfx_test_hash_buffer_overruns+0x10/0x10\n    kunit_try_run_case+0x198/0xa00\n\nThis occurs when memset() is called on a buffer that is not 4-byte aligned\nand extends to the end of a guard page, i.e.  the next page is unmapped.\n\nThe bug is that the loop at the end of kmsan_internal_set_shadow_origin()\naccesses the wrong shadow memory bytes when the address is not 4-byte\naligned.  Since each 4 bytes are associated with an origin, it rounds the\naddress and size so that it can access all the origins that contain the\nbuffer.  However, when it checks the corresponding shadow bytes for a\nparticular origin, it incorrectly uses the original unrounded shadow\naddress.  This results in reads from shadow memory beyond the end of the\nbuffer's shadow memory, which crashes when that memory is not mapped.\n\nTo fix this, correctly align the shadow address before accessing the 4\nshadow bytes corresponding to each origin.","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":"kmsan: fix out-of-bounds access to shadow memory","id":"CVE-2025-40008","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2025"},"n_packages":0,"n_references":5,"next":{"headline":"fs/proc/task_mmu: check p-\u003evec_buf for NULL","id":"CVE-2025-40009"},"packages":[],"prev":{"headline":"netfs: fix reference leak","id":"CVE-2025-40007"},"products":["Linux"],"published":"2025-10-20","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-23","vendors":["Linux"]},"summary":"A bug in KMSAN shadow memory handling causes a kernel crash when processing unaligned buffers near guard pages, requiring a patched kernel.","url":"https://insights.sbomify.com/CVE-2025-40008/"}