fkie_cve-2025-40190
Vulnerability from fkie_nvd
Published
2025-11-12 22:15
Modified
2025-11-14 16:42
Severity ?
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3d6269028246f4484bfed403c947a114bb583631
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/440b003f449a4ff2a00b08c8eab9ba5cd28f3943
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/505e69f76ac497e788f4ea0267826ec7266b40c8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/57295e835408d8d425bef58da5253465db3d6888
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b879c4c6bbaab03c0ad2a983953bd1410bb165e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/79ea7f3e11effe1bd9e753172981d9029133a278
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea39e712c2f5ae148ee5515798ae03523673e002
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2025-40190",
  "lastModified": "2025-11-14T16:42:30.503",
  "metrics": {},
  "published": "2025-11-12T22:15:45.960",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1cfb3e4ddbdc8e02e637b8852540bd4718bf4814"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3d6269028246f4484bfed403c947a114bb583631"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/440b003f449a4ff2a00b08c8eab9ba5cd28f3943"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/505e69f76ac497e788f4ea0267826ec7266b40c8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/57295e835408d8d425bef58da5253465db3d6888"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b879c4c6bbaab03c0ad2a983953bd1410bb165e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/79ea7f3e11effe1bd9e753172981d9029133a278"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ea39e712c2f5ae148ee5515798ae03523673e002"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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