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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 0.17% probability · 6th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814
- https://git.kernel.org/stable/c/3d6269028246f4484bfed403c947a114bb583631
- https://git.kernel.org/stable/c/440b003f449a4ff2a00b08c8eab9ba5cd28f3943
- https://git.kernel.org/stable/c/505e69f76ac497e788f4ea0267826ec7266b40c8
- https://git.kernel.org/stable/c/57295e835408d8d425bef58da5253465db3d6888
- https://git.kernel.org/stable/c/6b879c4c6bbaab03c0ad2a983953bd1410bb165e
- https://git.kernel.org/stable/c/79ea7f3e11effe1bd9e753172981d9029133a278
- https://git.kernel.org/stable/c/ea39e712c2f5ae148ee5515798ae03523673e002
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.