CVE-2025-71292: linux kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: jfs: nlink overflow in jfs_rename If nlink is maximal for a directory (-1) and inside that directory you perform a rename for some child directory (not moving from the parent), then the nlink of the first directory is first incremented and later decremented. Normally this is fine, but when nlink = -1 this causes a wrap around to 0, and then drop_nlink issues a warning. After applying the patch syzbot no longer issues any warnings. I also ran some basic fs tests to look for any regressions.
CVE-2025-71292CVSS 5.5Linux

CVE-2025-71292: linux kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: jfs: nlink overflow in jfs_rename If nlink is maximal for a directory (-1) and inside that directory you perform a rename for some child directory (not moving from the parent), then the nlink of the first directory is first incremented and later decremented. Normally this is fine, but when nlink = -1 this causes a wrap around to 0, and then drop_nlink issues a warning. After applying the patch syzbot no longer issues any warnings. I also ran some basic fs tests to look for any regressions.

CVSS
5.5 MEDIUM
EPSS
2.82%
Known exploited
not in KEV
Product
linux kernel

What is known

In the Linux kernel, the following vulnerability has been resolved: jfs: nlink overflow in jfs_rename If nlink is maximal for a directory (-1) and inside that directory you perform a rename for some child directory (not moving from the parent), then the nlink of the first directory is first incremented and later decremented. Normally this is fine, but when nlink = -1 this causes a wrap around to 0, and then drop_nlink issues a warning. After applying the patch syzbot no longer issues any warnings. I also ran some basic fs tests to look for any regressions.

Sources

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