Memory disclosure via bulk response over-read
Published Jul 25, 2026 · Updated Jul 25, 2026
Out-of-bounds read in the USBIO bridge driver in Linux Kernel 6.18 allows physically proximate attackers to disclose kernel memory. usbio_bulk_msg() bounds a device-controlled bulk IN payload length against the transmit buffer size, then copies that length from the smaller receive buffer. Exploitation requires a matching USB device with unequal endpoint sizes, bulk-path traffic, and user-space access through i2c-dev; the result is adjacent slab-memory disclosure rather than a write or code execution.
Summary
What happened
Out-of-bounds read in the USBIO bridge driver in Linux Kernel 6.18 allows physically proximate attackers to disclose kernel memory. usbio_bulk_msg() bounds a device-controlled bulk IN payload length against the transmit buffer size, then copies that length from the smaller receive buffer. Exploitation requires a matching USB device with unequal endpoint sizes, bulk-path traffic, and user-space access through i2c-dev; the result is adjacent slab-memory disclosure rather than a write or code execution.
The record
- CVE
- CVE-2026-64339
- Published
- Jul 25, 2026
- Updated
- Jul 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-125, T1005
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 25, 2026CVE publishedPublication date reported by the CVE source.
- Jul 25, 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.
- Affected versionversion=121a0f839dbb397af5fabb701cea3e9983223e50 <48394f94211cf8fe0ea8604fc441633abf90fc94
- Affected versionversion=121a0f839dbb397af5fabb701cea3e9983223e50 <8c6314489550fa81d41723a0ff33f655b5b6c7b6
- Affected versionversion=121a0f839dbb397af5fabb701cea3e9983223e50 <fc1b546973c1442d5b947fcdd03581f20ecc5bd2
- Affected versionversion=6.18
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
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
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo