title: Linux kernel io_uring PROVIDE_BUFFERS MAX_RW_COUNT  bypass
description: The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
problem types: CWE-131 Incorrect Calculation of Buffer Size
affected:
{
product: Linux kernel
vendor: Linux
versions:
lessThan: v5.13-rc4, status: affected, version: trunk, versionType: custom
lessThan: v5.12.4, status: affected, version: linux-5.12.y, versionType: custom
lessThan: v5.11.21, status: affected, version: linux-5.11.y, versionType: custom
lessThan: v5.10.37, status: affected, version: linux-5.10.y, versionType: custom
lessThan: 5.7*, status: affected, version: v5.7-rc1, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: LOCAL
availabilityImpact: HIGH
baseScore: 7.8
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: LOW
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
version: 3.1
]