Answer in brief
CVE-2025-40205 records a High severity (CVSS 7.8) vulnerability in btrfs: avoid potential out-of-bounds in btrfs_encode_fh(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <742b44342204e5dfe3926433823623c1a0c581df || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <d3a9a8e1275eb9b87f006b5562a287aea3f6885f || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <d91f6626133698362bba08fbc04bd72c466806d3 || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <0276c8582488022f057b4cec21975a5edf079f47 || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <361d67276eb8ec6be8f27f4ad6c6090459438fee || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <43143776b0a7604d873d1a6f3e552a00aa930224 || >=be6e8dc0ba84029997075a1ec77b4ddb863cbe15 <dff4f9ff5d7f289e4545cc936362e01ed3252742 | 60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db, 742b44342204e5dfe3926433823623c1a0c581df, d3a9a8e1275eb9b87f006b5562a287aea3f6885f, d91f6626133698362bba08fbc04bd72c466806d3, 0276c8582488022f057b4cec21975a5edf079f47, 361d67276eb8ec6be8f27f4ad6c6090459438fee, 43143776b0a7604d873d1a6f3e552a00aa930224, dff4f9ff5d7f289e4545cc936362e01ed3252742 |
| Linux/Linuxgeneric | 2.6.29 | Not reported |
Published upstream
Nov 12, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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, this write goes out of bounds because BTRFS_FID_SIZE_CONNECTABLE_ROOT is greater than BTRFS_FID_SIZE_CONNECTABLE originally returned. This results in an 8-byte out-of-bounds write at fid->parent_root_objectid = parent_root_id. A previous attempt to fix this issue was made but was lost. https://lore.kernel.org/all/[email protected]/ Although this issue does not seem to be easily triggerable, it is a potential memory corruption bug that should be fixed. This patch resolves the issue by ensuring the function returns the appropriate size for all three cases and validates that *max_len is large enough before writing any data.
Quoted source text, attributed separately from HOL analysis.