{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23233 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23233 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Mar 2026. 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-2026-23233 and fix it if it is affected.\n\nWhat it is: CVE-2026-23233 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Mar 2026. 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-2026-23233 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-2026-23233/ (Markdown: https://insights.sbomify.com/CVE-2026-23233/index.md)","id":"CVE-2026-23233","markdown":"https://insights.sbomify.com/CVE-2026-23233/index.md","name":"CVE-2026-23233","record":{"aliases":["BELL-CVE-2026-23233","DEBIAN-CVE-2026-23233","GHSA-p99w-mp33-jg8x","ROOT-OS-DEBIAN-13-CVE-2026-23233","ROOT-OS-UBUNTU-2404-CVE-2026-23233","UBUNTU-CVE-2026-23233"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["data_modify","denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel F2FS","requires_auth":"low_privilege","summary":"A flaw in the Linux kernel F2FS filesystem causes incorrect physical block mapping for small swapfiles, leading to data corruption and system crashes.","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":7.8,"severity":"high","source":"nvd","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-787","name":"Out-of-bounds Write"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid mapping wrong physical block for swapfile\n\nXiaolong Guo reported a f2fs bug in bugzilla [1]\n\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=220951\n\nQuoted:\n\n\"When using stress-ng's swap stress test on F2FS filesystem with kernel 6.6+,\nthe system experiences data corruption leading to either:\n1 dm-verity corruption errors and device reboot\n2 F2FS node corruption errors and boot hangs\n\nThe issue occurs specifically when:\n1 Using F2FS filesystem (ext4 is unaffected)\n2 Swapfile size is less than F2FS section size (2MB)\n3 Swapfile has fragmented physical layout (multiple non-contiguous extents)\n4 Kernel version is 6.6+ (6.1 is unaffected)\n\nThe root cause is in check_swap_activate() function in fs/f2fs/data.c. When the\nfirst extent of a small swapfile (\u003c 2MB) is not aligned to section boundaries,\nthe function incorrectly treats it as the last extent, failing to map\nsubsequent extents. This results in incorrect swap_extent creation where only\nthe first extent is mapped, causing subsequent swap writes to overwrite wrong\nphysical locations (other files' data).\n\nSteps to Reproduce\n1 Setup a device with F2FS-formatted userdata partition\n2 Compile stress-ng from https://github.com/ColinIanKing/stress-ng\n3 Run swap stress test: (Android devices)\nadb shell \"cd /data/stressng; ./stress-ng-64 --metrics-brief --timeout 60\n--swap 0\"\n\nLog:\n1 Ftrace shows in kernel 6.6, only first extent is mapped during second\nf2fs_map_blocks call in check_swap_activate():\nstress-ng-swap-8990: f2fs_map_blocks: ino=11002, file offset=0, start\nblkaddr=0x43143, len=0x1\n(Only 4KB mapped, not the full swapfile)\n2 in kernel 6.1, both extents are correctly mapped:\nstress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=0, start\nblkaddr=0x13cd4, len=0x1\nstress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=1, start\nblkaddr=0x60c84b, len=0xff\n\nThe problematic code is in check_swap_activate():\nif ((pblock - SM_I(sbi)-\u003emain_blkaddr) % blks_per_sec ||\n    nr_pblocks % blks_per_sec ||\n    !f2fs_valid_pinned_area(sbi, pblock)) {\n    bool last_extent = false;\n\n    not_aligned++;\n\n    nr_pblocks = roundup(nr_pblocks, blks_per_sec);\n    if (cur_lblock + nr_pblocks \u003e sis-\u003emax)\n        nr_pblocks -= blks_per_sec;\n\n    /* this extent is last one */\n    if (!nr_pblocks) {\n        nr_pblocks = last_lblock - cur_lblock;\n        last_extent = true;\n    }\n\n    ret = f2fs_migrate_blocks(inode, cur_lblock, nr_pblocks);\n    if (ret) {\n        if (ret == -ENOENT)\n            ret = -EINVAL;\n        goto out;\n    }\n\n    if (!last_extent)\n        goto retry;\n}\n\nWhen the first extent is unaligned and roundup(nr_pblocks, blks_per_sec)\nexceeds sis-\u003emax, we subtract blks_per_sec resulting in nr_pblocks = 0. The\ncode then incorrectly assumes this is the last extent, sets nr_pblocks =\nlast_lblock - cur_lblock (entire swapfile), and performs migration. After\nmigration, it doesn't retry mapping, so subsequent extents are never processed.\n\"\n\nIn order to fix this issue, we need to lookup block mapping info after\nwe migrate all blocks in the tail of swapfile.","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":"f2fs: fix to avoid mapping wrong physical block for swapfile","id":"CVE-2026-23233","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"memory_corruption","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"f2fs: fix to avoid UAF in f2fs_write_end_io()","id":"CVE-2026-23234"},"packages":[],"prev":{"headline":"Revert \"f2fs: block cache/dio write during f2fs_enable_checkpoint()\"","id":"CVE-2026-23232"},"products":["Linux"],"published":"2026-03-04","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":"2026-05-23","vendors":["Linux"]},"summary":"A flaw in the Linux kernel F2FS filesystem causes incorrect physical block mapping for small swapfiles, leading to data corruption and system crashes.","url":"https://insights.sbomify.com/CVE-2026-23233/"}