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CVE Record

CVE-2025-40056: vhost: vringh: Fix copy_to_iter return value check

In the Linux kernel, the following vulnerability has been resolved: vhost: vringh: Fix copy_to_iter return value check The return value of copy_to_iter can't be negative, check whether the copied length is equal to the requested length instead of checking for negative values.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

A Linux kernel bug in virtual host ring handling was fixed. The public record says the code checked a copy result incorrectly, which could mishandle partial copies. The source does not describe business impact, attack prerequisites, or confirmed exploitation, so urgency depends on affected kernel deployment and vendor assessment.

Executive priority

Treat as a monitored kernel maintenance item until more impact detail appears. Patch during normal kernel update cycles, with higher priority for virtualization infrastructure if vendor advisories confirm relevance or raise severity.

Technical view

The issue is an incorrect return-value check in vhost vringh. copy_to_iter returns the number of bytes copied, not a negative error. The fix checks whether the copied length equals the requested length. The source does not state impact such as crash, memory corruption, privilege escalation, or data exposure.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions or vendor builds containing the vulnerable vhost/vringh code. The record lists Linux kernel affected versions but provides no CPEs, distro mapping, or configuration requirements, so validate by kernel version and vendor backport status.

Exploitation context

No active exploitation is supported by the provided bundle. KEV is false, and the cited sources are CVE and Linux stable commit references. The bundle does not include exploit reports, proof-of-concept details, or attack prerequisites.

Researcher notes

The record identifies a logic error in return handling but omits impact analysis. Avoid assuming exploitability from the code area alone. Research should focus on affected call paths, whether partial copy handling can cause security impact, and which stable branches include the fix.

Mitigation direction

  • Apply the relevant Linux stable kernel fix or vendor kernel update.
  • Check distribution advisories for backported fixes and package versions.
  • Prioritize systems using virtualization features until impact is clarified.
  • Track the CVE record for severity, CWE, and impact updates.

Validation and detection

  • Inventory Linux kernel versions across affected hosts.
  • Confirm whether vendor kernels include one of the referenced stable fixes.
  • Review virtualization hosts first because the fix is in vhost/vringh code.
  • Document systems deferred due to maintenance windows or vendor dependency.
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-2025-40056 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

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

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
LinuxLinux309bba39c945ac8ab8083ac05cd6cfe5822968e0, 309bba39c945ac8ab8083ac05cd6cfe5822968e0, 309bba39c945ac8ab8083ac05cd6cfe5822968e0, 309bba39c945ac8ab8083ac05cd6cfe5822968e0, 309bba39c945ac8ab8083ac05cd6cfe5822968e0unaffected
LinuxLinux6.0, 0, 6.1.156, 6.6.112, 6.12.53, 6.17.3, 6.18affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.