CVE-2025-40246 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/678e1cc2f482e0985a0613ab4a5bf89c497e5acc
https://git.kernel.org/stable/c/7c2d68e091584149fe89bcbaf9b99b3162d46ee7
https://git.kernel.org/stable/c/81a8685cac4bf081c93a7df591644f4f80240bb9

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: xfs: fix out of bounds memory read error in symlink repair xfs/286 produced this report on my test fleet: ================================================================== BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110 Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184): memcpy_orig+0x54/0x110 xrep_symlink_salvage_inline+0xb3/0xf0 [xfs] xrep_symlink_salvage+0x100/0x110 [xfs] xrep_symlink+0x2e/0x80 [xfs] xrep_attempt+0x61/0x1f0 [xfs] xfs_scrub_metadata+0x34f/0x5c0 [xfs] xfs_ioc_scrubv_metadata+0x387/0x560 [xfs] xfs_file_ioctl+0xe23/0x10e0 [xfs] __x64_sys_ioctl+0x76/0xc0 do_syscall_64+0x4e/0x1e0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128 allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago): xfs_init_local_fork+0x79/0xe0 [xfs] xfs_iformat_local+0xa4/0x170 [xfs] xfs_iformat_data_fork+0x148/0x180 [xfs] xfs_inode_from_disk+0x2cd/0x480 [xfs] xfs_iget+0x450/0xd60 [xfs] xfs_bulkstat_one_int+0x6b/0x510 [xfs] xfs_bulkstat_iwalk+0x1e/0x30 [xfs] xfs_iwalk_ag_recs+0xdf/0x150 [xfs] xfs_iwalk_run_callbacks+0xb9/0x190 [xfs] xfs_iwalk_ag+0x1dc/0x2f0 [xfs] xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs] xfs_iwalk+0xa4/0xd0 [xfs] xfs_bulkstat+0xfa/0x170 [xfs] xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs] xfs_file_ioctl+0xbf2/0x10e0 [xfs] __x64_sys_ioctl+0x76/0xc0 do_syscall_64+0x4e/0x1e0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy) 3d744dd94e92690f00a04398d2bd8631dcef1954 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014 ================================================================== On further analysis, I realized that the second parameter to min() is not correct. xfs_ifork::if_bytes is the size of the xfs_ifork::if_data buffer. if_bytes can be smaller than the data fork size because: (a) the forkoff code tries to keep the data area as large as possible (b) for symbolic links, if_bytes is the ondisk file size + 1 (c) forkoff is always a multiple of 8. Case in point: for a single-byte symlink target, forkoff will be 8 but the buffer will only be 2 bytes long. In other words, the logic here is wrong and we walk off the end of the incore buffer. Fix that.
Title		xfs: fix out of bounds memory read error in symlink repair
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/678e1cc2f482e0985a0613ab4a5bf89c497e5acc https://git.kernel.org/stable/c/7c2d68e091584149fe89bcbaf9b99b3162d46ee7 https://git.kernel.org/stable/c/81a8685cac4bf081c93a7df591644f4f80240bb9

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-40246", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.181Z", "datePublished": "2025-12-04T16:08:09.751Z", "dateUpdated": "2025-12-04T16:08:09.751Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-12-04T16:08:09.751Z"}, "descriptions": [{"lang": "en", "value": "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."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/xfs/scrub/symlink_repair.c"], "versions": [{"version": "2651923d8d8db00a57665822f017fa7c76758044", "lessThan": "7c2d68e091584149fe89bcbaf9b99b3162d46ee7", "status": "affected", "versionType": "git"}, {"version": "2651923d8d8db00a57665822f017fa7c76758044", "lessThan": "81a8685cac4bf081c93a7df591644f4f80240bb9", "status": "affected", "versionType": "git"}, {"version": "2651923d8d8db00a57665822f017fa7c76758044", "lessThan": "678e1cc2f482e0985a0613ab4a5bf89c497e5acc", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/xfs/scrub/symlink_repair.c"], "versions": [{"version": "6.10", "status": "affected"}, {"version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.60", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.10", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.12.60"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.17.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.18"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/7c2d68e091584149fe89bcbaf9b99b3162d46ee7"}, {"url": "https://git.kernel.org/stable/c/81a8685cac4bf081c93a7df591644f4f80240bb9"}, {"url": "https://git.kernel.org/stable/c/678e1cc2f482e0985a0613ab4a5bf89c497e5acc"}], "title": "xfs: fix out of bounds memory read error in symlink repair", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2025-40246", "lastModified": "2025-12-04T17:15:08.283", "metrics": {}, "published": "2025-12-04T16:16:17.970", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/678e1cc2f482e0985a0613ab4a5bf89c497e5acc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7c2d68e091584149fe89bcbaf9b99b3162d46ee7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/81a8685cac4bf081c93a7df591644f4f80240bb9"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

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