CVE-2025-40205 Affecting kernel-uek-debug-core package, versions <0:5.15.0-315.196.5.1.el9uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.03% (9th percentile)

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  • Snyk IDSNYK-ORACLE9-KERNELUEKDEBUGCORE-14409915
  • published13 Dec 2025
  • disclosed12 Nov 2025

Introduced: 12 Nov 2025

CVE-2025-40205  (opens in a new tab)

How to fix?

Upgrade Oracle:9 kernel-uek-debug-core to version 0:5.15.0-315.196.5.1.el9uek or higher.
This issue was patched in ELSA-2025-28048.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek-debug-core package and not the kernel-uek-debug-core package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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/4CADAEEC020000780001B32C@vpn.id2.novell.com/

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.

CVSS Base Scores

version 3.1