Kernel memory corruption via oversized USB 9pfs payload
Published Oct 20, 2025 · Updated Oct 20, 2025
Heap buffer overflow in the Linux USB 9pfs transport allows physically proximate attackers to corrupt kernel memory via a malicious USB host. usb9pfs_rx_header validates only the packet's declared size, while usb9pfs_rx_complete copies the larger actual transfer length into the allocated receive buffer. Reachability requires an enabled 9pfs USB gadget connected to a malicious host; the published record establishes heap corruption but no further outcome.
Summary
What happened
Heap buffer overflow in the Linux USB 9pfs transport allows physically proximate attackers to corrupt kernel memory via a malicious USB host. usb9pfs_rx_header validates only the packet's declared size, while usb9pfs_rx_complete copies the larger actual transfer length into the allocated receive buffer. Reachability requires an enabled 9pfs USB gadget connected to a malicious host; the published record establishes heap corruption but no further outcome.
The record
- CVE
- CVE-2025-40004
- Published
- Oct 20, 2025
- Updated
- Oct 20, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 20, 2025CVE publishedPublication date reported by the CVE source.
- Oct 20, 2025Record 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=6.12
- Affected versionversion=a3be076dc174d9022a71a12554feb4c97b5c4d5c <0da18d49f874d444ad83c8a546fa33bfcf2f582c
- Affected versionversion=a3be076dc174d9022a71a12554feb4c97b5c4d5c <c04db81cd0288dfc68b7a0f7d09bd49b40bba451
- Affected versionversion=a3be076dc174d9022a71a12554feb4c97b5c4d5c <df8462f0fc045b4475dc494a5787a03c972ba2a2
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
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
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