CVE-2025-21724: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-27 · updated 2026-10-15
Weakness: CWE-787

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.

Affected products

Linux kernel: from 6.1 before 6.1.129; from 6.2 before 6.6.76; from 6.7 before 6.12.13; from 6.13 before 6.13.2 — fixed in 6.1.129, 6.12.13, 6.13.2, 6.6.76

How to fix

Upgrade to a fixed version: Linux kernel 6.1.129, 6.12.13, 6.13.2, 6.6.76. Check the vendor advisory for mitigations.

References

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