CVE-2026-64456

Guest-kernel heap disclosure via unchecked virtio length

Published Jul 25, 2026 · Updated Jul 25, 2026

Out-of-bounds read in the Linux Kernel virtio-rng driver allows attackers to disclose guest-kernel heap data through a crafted device length. random_recv_done() trusts the device-reported used.len, and copy_data() uses it for memcpy() without bounding the length and index to vi->data. The over-read starts when the device is probed without guest userspace action; direct disclosure through /dev/hwrng requires a malicious hypervisor and compromised guest root.

CVSS severity7.7
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux Kernel virtio-rng driver allows attackers to disclose guest-kernel heap data through a crafted device length. random_recv_done() trusts the device-reported used.len, and copy_data() uses it for memcpy() without bounding the length and index to vi->data. The over-read starts when the device is probed without guest userspace action; direct disclosure through /dev/hwrng requires a malicious hypervisor and compromised guest root.

The record

CVE
CVE-2026-64456
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1005
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 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=2.6.26
  2. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <285e17c44e3873a73460f294acbd64018ff64385
  3. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <2e788948ff2a13358a303af112497a63201c5739
  4. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <3aa3e89cf80721c8d382b4c1a2b70a0449dad4a5
  5. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <63335e7b638ae70028ae285bb95153874a8bc852
  6. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <81dd21b5f0c299cc7b5bf84f04a61938559d20e6
  7. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <92d5736a62040ec1cfff23ea57e6599301690ad5
  8. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <e3046eeada299f917a8ad883af4434bfb86556b1
  9. Affected versionversion=f7f510ec195781c857ab76366a3e1c59e1caae42 <fde19b0d4eeabae042519313c843fe6f27d41e9d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.26; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <285e17c44e3873a73460f294acbd64018ff64385; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <2e788948ff2a13358a303af112497a63201c5739; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <3aa3e89cf80721c8d382b4c1a2b70a0449dad4a5; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <63335e7b638ae70028ae285bb95153874a8bc852; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <81dd21b5f0c299cc7b5bf84f04a61938559d20e6; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <92d5736a62040ec1cfff23ea57e6599301690ad5; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <e3046eeada299f917a8ad883af4434bfb86556b1; version=f7f510ec195781c857ab76366a3e1c59e1caae42 <fde19b0d4eeabae042519313c843fe6f27d41e9d

Published CVSS scores

7.7Linux kernel CVE teamCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1005Data from Local System

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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