CVE-2025-21876

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-03-27. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Fix suspicious RCU usage

Commit ("iommu/vt-d: Allocate DMAR fault interrupts locally") moved the call to enable_drhd_fault_handling() to a code path that does not hold any lock while traversing the drhd list. Fix it by ensuring the dmar_global_lock lock is held when traversing the drhd list.

Without this fix, the following warning is triggered: ============================= WARNING: suspicious RCU usage 6.14.0-rc3 #55 Not tainted ----------------------------- drivers/iommu/intel/dmar.c:2046 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by cpuhp/1/23: #0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0 #1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0 stack backtrace: CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 Not tainted 6.14.0-rc3 #55 Call Trace: dump_stack_lvl+0xb7/0xd0 lockdep_rcu_suspicious+0x159/0x1f0 ? __pfx_enable_drhd_fault_handling+0x10/0x10 enable_drhd_fault_handling+0x151/0x180 cpuhp_invoke_callback+0x1df/0x990 cpuhp_thread_fun+0x1ea/0x2c0 smpboot_thread_fn+0x1f5/0x2e0 ? __pfx_smpboot_thread_fn+0x10/0x10 kthread+0x12a/0x2d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x4a/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30

Holding the lock in enable_drhd_fault_handling() triggers a lockdep splat about a possible deadlock between dmar_global_lock and cpu_hotplug_lock. This is avoided by not holding dmar_global_lock when calling iommu_device_register(), which initiates the device probe process.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

March 27, 2025

Last Modified

August 5, 2026

Advisory Details (3)

Auto-updated Aug 2, 2026
No patch confirmed yet.
generic

iommu/vt-d: Fix suspicious RCU usage - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c603ccbe91d189849e1439134598ec567088dcec
generic

iommu/vt-d: Fix suspicious RCU usage - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b150654f74bf0df8e6a7936d5ec51400d9ec06d8
generic

iommu/vt-d: Fix suspicious RCU usage - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4117c72938493a77ab53cc4b8284be8fb6ec8065

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-aws (6.11.0-1014.15) @ oracular2026-05-30ubuntu
ubuntulinux-tools-oracle-64k (6.11.0-1016.17) @ oracular2026-05-30ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-26.26~24.04.1) @ noble2026-05-30ubuntu
linuxKernel @ 6.12.18—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(3)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 10× in last 7d / 45× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 115 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-05 19:16 UTCEPSS rescore
  4. 2026-08-05 14:01 UTCEG score recompute
  5. 2026-08-05 14:01 UTCVendor advisory
  6. 2026-08-05 14:01 UTCGHSA enrichment
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  14. 2026-07-30 07:19 UTCGHSA enrichment
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  21. 2026-07-24 10:41 UTCOSV refresh
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  23. 2026-07-23 02:50 UTCEG score recompute
  24. 2026-07-22 14:07 UTCEPSS rescore
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  1. 2026-07-21 15:24 UTCEPSS rescore
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  21. 2026-07-08 15:14 UTCEPSS rescore
  22. 2026-07-07 13:45 UTCEPSS rescore
  23. 2026-07-07 06:21 UTCOSV refresh
  24. 2026-07-06 16:26 UTCEPSS rescore
  25. 2026-07-06 02:22 UTCEPSS rescore
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  27. 2026-07-05 02:30 UTCEPSS rescore
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  49. 2026-06-21 01:59 UTCEPSS rescore
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  51. 2026-06-19 19:25 UTCEPSS rescore
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  53. 2026-06-18 17:52 UTCEPSS rescore
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  55. 2026-06-18 17:35 UTCOSV refresh
  56. 2026-06-17 17:52 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-21876?
CVE-2025-21876 is a medium vulnerability published on March 27, 2025. In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix suspicious RCU usage Commit <d74169ceb0d2> ("iommu/vt-d: Allocate DMAR fault interrupts locally") moved the call to enabledrhdfault_handling() to a code path that does not hold any lock while traversing the drhd…
When was CVE-2025-21876 disclosed?
CVE-2025-21876 was first published in the National Vulnerability Database on March 27, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21876 actively exploited?
CVE-2025-21876 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 89.8% of all scored CVEs.
What is the CVSS score of CVE-2025-21876?
CVE-2025-21876 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21876?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21876, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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