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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2025-21724

Linux kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index()

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.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2025-21724 (opens a new tab)

What happened

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.

Continue reading

To resolve this, the constant is updated to "1UL", promoting it to an unsigned long type to match the operand's type.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2025-21724 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). Linux kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() (CVE-2025-21724). https://kevwire.com/record/CVE-2025-21724

MLA

"Linux kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() (CVE-2025-21724)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2025-21724.

Chicago

KEVWire. "Linux kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() (CVE-2025-21724)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2025-21724.

Evidence summary (plain text)

Linux kernel: iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index() (Feb 27, 2025).
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.
CVSS 7.8 (version 3.1; evidence as of Nov 5, 2026; https://nvd.nist.gov/vuln/detail/CVE-2025-21724).
Sources:
NVD CVE-2025-21724: https://nvd.nist.gov/vuln/detail/CVE-2025-21724
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T20:51:23.450Z&lastModEndDate=2026-11-05T22:25:57.582Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T20:16:05.862Z&lastModEndDate=2026-11-05T21:50:58.884Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2025-21724.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 22:25 UTC. Ingestion is not an independent editorial investigation.

NVD status: Modified. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail