CVE-2025-40190
In the Linux kernel, the following vulnerability has been resolved: ext4: guard against EA inode refcount underflow in xattr update syzkaller found a path where ext4_xattr_inode_update_ref() reads an EA inode refcount that is already <= 0 and then applies ref_change (often -1). That lets the refcount underflow and we proceed with a bogus value, triggering errors like: EXT4-fs error: EA inode <n> ref underflow: ref_count=-1 ref_change=-1 EXT4-fs warning: ea_inode dec ref err=-117 Make the invariant explicit: if the current refcount is non-positive, treat this as on-disk corruption, emit ext4_error_inode(), and fail the operation with -EFSCORRUPTED instead of updating the refcount. Delete the WARN_ONCE() as negative refcounts are now impossible; keep error reporting in ext4_error_inode(). This prevents the underflow and the follow-on orphan/cleanup churn.
Affected versions
Fixed in
5.4.301,
5.10.246,
5.15.195,
6.1.157,
6.6.113,
6.12.54,
6.17.4,
6.18
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2025-40190?
CVE-2025-40190 is a unscored severity Linux kernel vulnerability . CVE-2025-40190 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40190?
Yes. CVE-2025-40190 has been patched. Fixed versions include 5.4.301, 5.10.246, 5.15.195 and others.
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Is CVE-2025-40190 actively exploited?
No. CVE-2025-40190 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.