GHSA-J9X6-GMQ6-XM5X
Vulnerability from github – Published: 2025-11-13 00:30 – Updated: 2026-07-30 06:32In 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 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": [],
"aliases": [
"CVE-2025-40190"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-12T22:15:45Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: guard against EA inode refcount underflow in xattr update\n\nsyzkaller found a path where ext4_xattr_inode_update_ref() reads an EA\ninode refcount that is already \u003c= 0 and then applies ref_change (often\n-1). That lets the refcount underflow and we proceed with a bogus value,\ntriggering errors like:\n\n EXT4-fs error: EA inode \u003cn\u003e ref underflow: ref_count=-1 ref_change=-1\n EXT4-fs warning: ea_inode dec ref err=-117\n\nMake the invariant explicit: if the current refcount is non-positive,\ntreat this as on-disk corruption, emit ext4_error_inode(), and fail the\noperation with -EFSCORRUPTED instead of updating the refcount. Delete the\nWARN_ONCE() as negative refcounts are now impossible; keep error reporting\nin ext4_error_inode().\n\nThis prevents the underflow and the follow-on orphan/cleanup churn.",
"id": "GHSA-j9x6-gmq6-xm5x",
"modified": "2026-07-30T06:32:17Z",
"published": "2025-11-13T00:30:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40190"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d6269028246f4484bfed403c947a114bb583631"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/440b003f449a4ff2a00b08c8eab9ba5cd28f3943"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/505e69f76ac497e788f4ea0267826ec7266b40c8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/57295e835408d8d425bef58da5253465db3d6888"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6b879c4c6bbaab03c0ad2a983953bd1410bb165e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/79ea7f3e11effe1bd9e753172981d9029133a278"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ea39e712c2f5ae148ee5515798ae03523673e002"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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