CVE-2025-39985

Kernel memory corruption via CAN XL length confusion

Published Oct 15, 2025 · Updated Aug 5, 2026

Buffer overflow in the Linux mcba_usb CAN driver allows local users to corrupt kernel memory via a crafted PF_PACKET CAN XL frame. mcba_usb_start_xmit misreads a CAN XL flags byte as a classic CAN length and copies up to 255 bytes into an eight-byte usb_msg.data buffer because the driver accepts an oversized interface MTU. Exploitation requires local CAP_NET_RAW access and an mcba_usb CAN interface; it can disclose kernel memory, escalate privileges, or crash the host.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in the Linux mcba_usb CAN driver allows local users to corrupt kernel memory via a crafted PF_PACKET CAN XL frame. mcba_usb_start_xmit misreads a CAN XL flags byte as a classic CAN length and copies up to 255 bytes into an eight-byte usb_msg.data buffer because the driver accepts an oversized interface MTU. Exploitation requires local CAP_NET_RAW access and an mcba_usb CAN interface; it can disclose kernel memory, escalate privileges, or crash the host.

The record

CVE
CVE-2025-39985
Published
Oct 15, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.12
  2. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <0fa9303c4b9493727e0d3a6ac3729300e3013930
  3. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <17c8d794527f01def0d1c8b7dc2d7b8d34fed0e6
  4. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <3664ae91b26d1fd7e4cee9cde17301361f4c89d5
  5. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <37aed407496bf6de8910e588edb04d2435fa7011
  6. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <6b9fb82df8868dbe9ffea5874b8d35f951faedbb
  7. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <6eec67bfb25637f9b51e584cf59ddace59925bc8
  8. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <b638c3fb0f163e69785ceddb3b434a9437878bec
  9. Affected versionversion=51f3baad7de943780ce0c17bd7975df567dd6e14 <ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.12; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <0fa9303c4b9493727e0d3a6ac3729300e3013930; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <17c8d794527f01def0d1c8b7dc2d7b8d34fed0e6; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <3664ae91b26d1fd7e4cee9cde17301361f4c89d5; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <37aed407496bf6de8910e588edb04d2435fa7011; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <6b9fb82df8868dbe9ffea5874b8d35f951faedbb; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <6eec67bfb25637f9b51e584cf59ddace59925bc8; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <b638c3fb0f163e69785ceddb3b434a9437878bec; version=51f3baad7de943780ce0c17bd7975df567dd6e14 <ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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