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Review reviewHigh

CVE-2025-40205

Linux

In the Linux kernel, the following vulnerability has been resolved: btrfs: avoid potential out-of-bounds in btrfs_encode_fh() The function btrfs_encode_fh() does not properly account for the three cases it handles. Before writing to the file handle (fh), the function only returns to the user BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) or BTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes). However, when a parent exists and the root ID of the parent and the inode are different, the function writes BTRFS_FID_SIZE_CONNECTABLE_ROOT (10 dwords, 40 bytes). If *max_len is not large enough, thi...

CVSS
7.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2025.11.13
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: btrfs: avoid potential out-of-bounds in btrfs_encode_fh() The function btrfs_encode_fh() does not properly account for the three cases it handles. Before writing to the file handle (fh), the function only returns to the user BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) or BTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes). However, when a parent exists and the root ID of the parent and the inode are different, the function writes BTRFS_FID_SIZE_CONNECTABLE_ROOT (10 dwords, 40 bytes). If *max_len is not large enough, thi...

Affected product and versions

Product
Linux
Affected versions
>= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < 60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < 742b44342204e5dfe3926433823623c1a0c581df, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < d3a9a8e1275eb9b87f006b5562a287aea3f6885f, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < d91f6626133698362bba08fbc04bd72c466806d3, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < 0276c8582488022f057b4cec21975a5edf079f47, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < 361d67276eb8ec6be8f27f4ad6c6090459438fee, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < 43143776b0a7604d873d1a6f3e552a00aa930224, >= be6e8dc0ba84029997075a1ec77b4ddb863cbe15 < dff4f9ff5d7f289e4545cc936362e01ed3252742, >= 2.6.29
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available