Summary
In the Linux kernel, the following vulnerability has been resolved: xfs: fix out of bounds...
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
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.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-40246? CVE-2025-40246 is a unknown-severity security vulnerability. No fixed version is listed yet.
- Is there a fix for CVE-2025-40246? No fixed version is listed for CVE-2025-40246 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-40246 exploitable, and should I be worried? Whether CVE-2025-40246 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-40246 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.