Out-of-bounds read in Linux kernel - CVE-2026-64456
Published: July 27, 2026
Vulnerability identifier: #VU139487
CSH Severity: High
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64456
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in the virtio-rng driver copy_data() function when processing device-reported used.len values from a virtio-rng backend. A remote attacker can provide a specially crafted length value to disclose sensitive information.
The issue can leak adjacent guest-kernel slab contents through the guest RNG and can also be observed directly via /dev/hwrng. No guest userspace interaction is required for the initial out-of-bounds read to occur.
Affected software
Linux kernel
How to mitigate CVE-2026-64456
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/285e17c44e3873a73460f294acbd64018ff64385
- https://git.kernel.org/stable/c/2e788948ff2a13358a303af112497a63201c5739
- https://git.kernel.org/stable/c/3aa3e89cf80721c8d382b4c1a2b70a0449dad4a5
- https://git.kernel.org/stable/c/63335e7b638ae70028ae285bb95153874a8bc852
- https://git.kernel.org/stable/c/81dd21b5f0c299cc7b5bf84f04a61938559d20e6
- https://git.kernel.org/stable/c/92d5736a62040ec1cfff23ea57e6599301690ad5
- https://git.kernel.org/stable/c/e3046eeada299f917a8ad883af4434bfb86556b1
- https://git.kernel.org/stable/c/fde19b0d4eeabae042519313c843fe6f27d41e9d