CVE-2025-21876

Local privilege escalation via unlocked DRHD list traversal

Published Mar 27, 2025 · Updated Aug 5, 2026

Race condition in Linux kernel 6.10 through 6.14-rc4 allows local users to corrupt kernel and IOMMU state during CPU-online events. The enable_drhd_fault_handling callback traverses the DRHD list without dmar_global_lock, allowing concurrent removal to leave a freed IOMMU descriptor supplying MMIO addresses to readl and writel. Reachability requires Intel VT-d and a local CPU-online or suspend/resume transition; exploitation provides kernel and DMA-isolation reads, writes, or crashes.

CVSS severity8.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux kernel 6.10 through 6.14-rc4 allows local users to corrupt kernel and IOMMU state during CPU-online events. The enable_drhd_fault_handling callback traverses the DRHD list without dmar_global_lock, allowing concurrent removal to leave a freed IOMMU descriptor supplying MMIO addresses to readl and writel. Reachability requires Intel VT-d and a local CPU-online or suspend/resume transition; exploitation provides kernel and DMA-isolation reads, writes, or crashes.

The record

CVE
CVE-2025-21876
Published
Mar 27, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.10
  2. Affected versionversion=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <4117c72938493a77ab53cc4b8284be8fb6ec8065
  3. Affected versionversion=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <b150654f74bf0df8e6a7936d5ec51400d9ec06d8
  4. Affected versionversion=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <c603ccbe91d189849e1439134598ec567088dcec

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.10; version=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <4117c72938493a77ab53cc4b8284be8fb6ec8065; version=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <b150654f74bf0df8e6a7936d5ec51400d9ec06d8; version=d74169ceb0d2e32438946a2f1f9fc8c803304bd6 <c603ccbe91d189849e1439134598ec567088dcec

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
8.8Linux Kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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