CVE-2025-40190
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Deferred
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-40190.md and follow it. Check whether this project is affected by CVE-2025-40190. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
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