CVE-2026-63893

Kernel heap disclosure via wrapped property offset

Published Jul 19, 2026 · Updated Jul 19, 2026

Out-of-bounds read in Linux Kernel allows physically proximate attackers to disclose kernel heap data through a crafted XDomain property. tb_property_entry_valid() adds the u32 entry value to the u16 length without overflow detection, so a wrapped sum passes the block-length check and parse_dwdata() treats the value as an out-of-range dword offset. A malicious peer must be connected over a direct Thunderbolt or USB4 XDomain link; TEXT deviceid or vendorid entries expose an untargeted, NUL-bounded leak through sysfs, and an unmapped offset can crash the kernel.

CVSS severity8.1
High
EPSS probability0.39%
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 Linux Kernel allows physically proximate attackers to disclose kernel heap data through a crafted XDomain property. tb_property_entry_valid() adds the u32 entry value to the u16 length without overflow detection, so a wrapped sum passes the block-length check and parse_dwdata() treats the value as an out-of-range dword offset. A malicious peer must be connected over a direct Thunderbolt or USB4 XDomain link; TEXT deviceid or vendorid entries expose an untargeted, NUL-bounded leak through sysfs, and an unmapped offset can crash the kernel.

The record

CVE
CVE-2026-63893
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=4.15
  2. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <01deda0152066c6c955f0619114ea6afa070aaec
  3. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <31b98e503ecca8077e5247253dd5425ab84bc96d
  4. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <5c06a3043ad944f087bb2ae0aae28d820bb9f460
  5. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <6a63623621639acbb39bc2d9fb09559681716695
  6. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <8d4a758b407ab3de3be86d1ceadfa35d717d30c7
  7. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <9fee50c4e1e42f6d3cbe30df584f9f648f626071
  8. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <a47784aee77f33f786dc5d7375db821bdae68792
  9. Affected versionversion=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.15; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <01deda0152066c6c955f0619114ea6afa070aaec; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <31b98e503ecca8077e5247253dd5425ab84bc96d; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <5c06a3043ad944f087bb2ae0aae28d820bb9f460; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <6a63623621639acbb39bc2d9fb09559681716695; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <8d4a758b407ab3de3be86d1ceadfa35d717d30c7; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <9fee50c4e1e42f6d3cbe30df584f9f648f626071; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <a47784aee77f33f786dc5d7375db821bdae68792; version=cdae7c07e3e3509eaabc18c1640a55dc5b99c179 <e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36

Published CVSS scores

8.1Linux kernel CVE teamCVSS:3.1/AV:A/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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