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Medium severity5.5NVD Advisory· Published May 1, 2024· Updated May 12, 2026

CVE-2024-26973

CVE-2024-26973

Description

In the Linux kernel, the following vulnerability has been resolved:

fat: fix uninitialized field in nostale filehandles

When fat_encode_fh_nostale() encodes file handle without a parent it stores only first 10 bytes of the file handle. However the length of the file handle must be a multiple of 4 so the file handle is actually 12 bytes long and the last two bytes remain uninitialized. This is not great at we potentially leak uninitialized information with the handle to userspace. Properly initialize the full handle length.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

An uninitialized field in Linux kernel's fat_encode_fh_nostale() leaks stack memory through file handles, fixed by proper initialization.

Vulnerability

The Linux kernel's VFAT filesystem implementation contains an information disclosure vulnerability in the fat_encode_fh_nostale() function. When encoding a file handle without a parent directory, the function stores only the first 10 bytes of the handle, but the handle must be padded to a multiple of 4 bytes, resulting in a 12-byte structure with the last two bytes left uninitialized [1][2]. This means kernel stack memory can be exposed to userspace.

Exploitation

The vulnerability is triggered when the kernel exports a file handle (e.g., via NFS or other file handle APIs) for a FAT filesystem inode that lacks a parent dentry. No special privileges are required; any user who can trigger such file handle encoding could potentially receive the uninitialized bytes. The attack surface is local or may be reachable through network filesystem operations that encode handles.

Impact

An attacker can obtain up to two bytes of uninitialized kernel stack memory. While the amount leaked is small, the leaked data could contain sensitive information such as kernel pointers or other secret data that might assist in bypassing KASLR or other mitigations.

Mitigation

The fix, committed to the Linux kernel stable tree, properly initializes the entire file handle structure before encoding [3][4]. Users should apply the kernel update containing the patch. Siemens has also addressed this CVE in their security advisory for affected SIMATIC products [1][2].

References
  1. SSA-398330
  2. SSA-265688
  3. Making sure you're not a bot!
  4. Making sure you're not a bot!

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

158

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

13

News mentions

0

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