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CVE Record

CVE-2025-38688: iommufd: Prevent ALIGN() overflow

In the Linux kernel, the following vulnerability has been resolved: iommufd: Prevent ALIGN() overflow When allocating IOVA the candidate range gets aligned to the target alignment. If the range is close to ULONG_MAX then the ALIGN() can wrap resulting in a corrupted iova. Open code the ALIGN() using get_add_overflow() to prevent this. This simplifies the checks as we don't need to check for length earlier either. Consolidate the two copies of this code under a single helper. This bug would allow userspace to create a mapping that overlaps with some other mapping or a reserved range.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in the Linux kernel’s I/O memory mapping subsystem can corrupt address allocation calculations. A locally authenticated, low-privilege user could potentially create a mapping that overlaps another mapping or protected range, threatening confidentiality, integrity, and availability. The issue matters most on systems exposing iommufd functionality to untrusted local users or workloads.

Executive priority

Prioritize remediation on shared Linux hosts, virtualization infrastructure, and systems running untrusted workloads. Internet exposure alone is not the primary condition because the documented attack vector is local. Complete an inventory and vendor-status check promptly; accelerate patching where low-privilege users can access iommufd.

Technical view

During IOVA allocation, aligning a candidate range near ULONG_MAX can overflow and wrap. The resulting corrupted IOVA may overlap an existing mapping or reserved range. The kernel fix replaces unsafe ALIGN() handling with overflow-aware arithmetic and consolidates duplicated validation logic.

Likely exposure

The supplied data identifies Linux kernel versions 6.2, 6.6.103, 6.12.43, 6.15.11, 6.16.2, and 6.17 as affected. Practical exposure depends on whether an untrusted local user or workload can access the vulnerable iommufd path. Distribution-specific status is not provided.

Exploitation context

The CVSS vector describes local, low-complexity exploitation requiring low privileges and no user interaction, with potential cross-scope impact. The supplied record is not in KEV and provides no evidence of active exploitation or a public exploit. Treat exploit prevalence as unknown rather than confirmed.

Researcher notes

The core invariant failure is integer wrap during alignment of an IOVA candidate near ULONG_MAX. That may bypass range expectations and permit overlap with mapped or reserved address space. The bundle supplies multiple stable-kernel commits but does not map each commit to a specific release or provide reproduction details.

Mitigation direction

  • Apply a vendor-supported kernel update containing the referenced overflow fix.
  • Check the Linux distribution’s advisory for exact affected and fixed package versions.
  • Prioritize multi-user, virtualization, and workload-hosting systems exposing iommufd to untrusted users.
  • Restrict untrusted local access to affected systems until updates are validated.

Validation and detection

  • Record each system’s running kernel and distribution package version.
  • Compare versions with current distribution guidance for CVE-2025-38688.
  • Determine whether untrusted local users or workloads can reach iommufd interfaces.
  • Confirm the installed kernel incorporates an applicable referenced stable fix.
  • Reboot into the updated kernel and verify the running version.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2025-38688 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H26Linux

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2025-38688Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux51fe6141f0f64ae0bbc096a41a07572273e8c0ef, 51fe6141f0f64ae0bbc096a41a07572273e8c0ef, 51fe6141f0f64ae0bbc096a41a07572273e8c0ef, 51fe6141f0f64ae0bbc096a41a07572273e8c0ef, 51fe6141f0f64ae0bbc096a41a07572273e8c0efunaffected
LinuxLinux6.2, 0, 6.6.103, 6.12.43, 6.15.11, 6.16.2, 6.17affected
Weakness

CWE details

No CWE listed

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