{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40246 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40246 is a memory corruption vulnerability in Linux, published on 4 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-2025-40246 and fix it if it is affected.\n\nWhat it is: CVE-2025-40246 is a memory corruption vulnerability in Linux, published on 4 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-2025-40246 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-2025-40246/ (Markdown: https://insights.sbomify.com/CVE-2025-40246/index.md)","id":"CVE-2025-40246","markdown":"https://insights.sbomify.com/CVE-2025-40246/index.md","name":"CVE-2025-40246","record":{"aliases":["BELL-CVE-2025-40246","DEBIAN-CVE-2025-40246","GHSA-x6g9-37j8-7qh9","ROOT-OS-DEBIAN-13-CVE-2025-40246","UBUNTU-CVE-2025-40246"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","data_read"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel XFS","requires_auth":"high_privilege","summary":"A local attacker with high privileges can trigger an out-of-bounds memory read in the XFS symlink repair code, potentially causing a system crash or leaking kernel memory.","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\nxfs: fix out of bounds memory read error in symlink repair\n\nxfs/286 produced this report on my test fleet:\n\n ==================================================================\n BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110\n\n Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):\n  memcpy_orig+0x54/0x110\n  xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]\n  xrep_symlink_salvage+0x100/0x110 [xfs]\n  xrep_symlink+0x2e/0x80 [xfs]\n  xrep_attempt+0x61/0x1f0 [xfs]\n  xfs_scrub_metadata+0x34f/0x5c0 [xfs]\n  xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]\n  xfs_file_ioctl+0xe23/0x10e0 [xfs]\n  __x64_sys_ioctl+0x76/0xc0\n  do_syscall_64+0x4e/0x1e0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128\n\n allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):\n  xfs_init_local_fork+0x79/0xe0 [xfs]\n  xfs_iformat_local+0xa4/0x170 [xfs]\n  xfs_iformat_data_fork+0x148/0x180 [xfs]\n  xfs_inode_from_disk+0x2cd/0x480 [xfs]\n  xfs_iget+0x450/0xd60 [xfs]\n  xfs_bulkstat_one_int+0x6b/0x510 [xfs]\n  xfs_bulkstat_iwalk+0x1e/0x30 [xfs]\n  xfs_iwalk_ag_recs+0xdf/0x150 [xfs]\n  xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]\n  xfs_iwalk_ag+0x1dc/0x2f0 [xfs]\n  xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]\n  xfs_iwalk+0xa4/0xd0 [xfs]\n  xfs_bulkstat+0xfa/0x170 [xfs]\n  xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]\n  xfs_file_ioctl+0xbf2/0x10e0 [xfs]\n  __x64_sys_ioctl+0x76/0xc0\n  do_syscall_64+0x4e/0x1e0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy)  3d744dd94e92690f00a04398d2bd8631dcef1954\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014\n ==================================================================\n\nOn further analysis, I realized that the second parameter to min() is\nnot correct.  xfs_ifork::if_bytes is the size of the xfs_ifork::if_data\nbuffer.  if_bytes can be smaller than the data fork size because:\n\n(a) the forkoff code tries to keep the data area as large as possible\n(b) for symbolic links, if_bytes is the ondisk file size + 1\n(c) forkoff is always a multiple of 8.\n\nCase in point: for a single-byte symlink target, forkoff will be\n8 but the buffer will only be 2 bytes long.\n\nIn other words, the logic here is wrong and we walk off the end of the\nincore buffer.  Fix that.","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":"xfs: fix out of bounds memory read error in symlink repair","id":"CVE-2025-40246","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2025"},"n_packages":0,"n_references":3,"next":{"headline":"drm/msm: Fix pgtable prealloc error path","id":"CVE-2025-40247"},"packages":[],"prev":{"headline":"nios2: ensure that memblock.current_limit is set when setting pfn limits","id":"CVE-2025-40245"},"products":["Linux"],"published":"2025-12-04","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":"2026-05-11","vendors":["Linux"]},"summary":"A local attacker with high privileges can trigger an out-of-bounds memory read in the XFS symlink repair code, potentially causing a system crash or leaking kernel memory.","url":"https://insights.sbomify.com/CVE-2025-40246/"}