{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-68211 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-68211 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Dec 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-2025-68211 and fix it if it is affected.\n\nWhat it is: CVE-2025-68211 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Dec 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-2025-68211 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-2025-68211/ (Markdown: https://insights.sbomify.com/CVE-2025-68211/index.md)","id":"CVE-2025-68211","markdown":"https://insights.sbomify.com/CVE-2025-68211/index.md","name":"CVE-2025-68211","record":{"aliases":["AZL-72419","AZL-78398","BELL-CVE-2025-68211","DEBIAN-CVE-2025-68211","GHSA-qhqr-mc3h-hmjp","ROOT-OS-DEBIAN-11-CVE-2025-68211","ROOT-OS-DEBIAN-12-CVE-2025-68211","ROOT-OS-DEBIAN-13-CVE-2025-68211","ROOT-OS-UBUNTU-2204-CVE-2025-68211","ROOT-OS-UBUNTU-2404-CVE-2025-68211","UBUNTU-CVE-2025-68211"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A local attacker can cause excessive CPU usage in the KSM daemon by creating sparse memory mappings, leading to a denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksm: use range-walk function to jump over holes in scan_get_next_rmap_item\n\nCurrently, scan_get_next_rmap_item() walks every page address in a VMA to\nlocate mergeable pages.  This becomes highly inefficient when scanning\nlarge virtual memory areas that contain mostly unmapped regions, causing\nksmd to use large amount of cpu without deduplicating much pages.\n\nThis patch replaces the per-address lookup with a range walk using\nwalk_page_range().  The range walker allows KSM to skip over entire\nunmapped holes in a VMA, avoiding unnecessary lookups.  This problem was\npreviously discussed in [1].\n\nConsider the following test program which creates a 32 TiB mapping in the\nvirtual address space but only populates a single page:\n\n#include \u003cunistd.h\u003e\n#include \u003cstdio.h\u003e\n#include \u003csys/mman.h\u003e\n\n/* 32 TiB */\nconst size_t size = 32ul * 1024 * 1024 * 1024 * 1024;\n\nint main() {\n        char *area = mmap(NULL, size, PROT_READ | PROT_WRITE,\n                          MAP_NORESERVE | MAP_PRIVATE | MAP_ANON, -1, 0);\n\n        if (area == MAP_FAILED) {\n                perror(\"mmap() failed\\n\");\n                return -1;\n        }\n\n        /* Populate a single page such that we get an anon_vma. */\n        *area = 0;\n\n        /* Enable KSM. */\n        madvise(area, size, MADV_MERGEABLE);\n        pause();\n        return 0;\n}\n\n$ ./ksm-sparse  \u0026\n$ echo 1 \u003e /sys/kernel/mm/ksm/run \n\nWithout this patch ksmd uses 100% of the cpu for a long time (more then 1\nhour in my test machine) scanning all the 32 TiB virtual address space\nthat contain only one mapped page.  This makes ksmd essentially deadlocked\nnot able to deduplicate anything of value.  With this patch ksmd walks\nonly the one mapped page and skips the rest of the 32 TiB virtual address\nspace, making the scan fast using little cpu.","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":"ksm: use range-walk function to jump over holes in scan_get_next_rmap_item","id":"CVE-2025-68211","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"fs: Fix uninitialized 'offp' in statmount_string()","id":"CVE-2025-68212"},"packages":[],"prev":{"headline":"erofs: avoid infinite loop due to incomplete zstd-compressed data","id":"CVE-2025-68210"},"products":["Linux"],"published":"2025-12-16","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":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-06-11","vendors":["Linux"]},"summary":"A local attacker can cause excessive CPU usage in the KSM daemon by creating sparse memory mappings, leading to a denial of service.","url":"https://insights.sbomify.com/CVE-2025-68211/"}