CVE-2021-3490 Linux kernel eBPF bitwise ops ALU32 bounds tracking

2021-05-1100:00:00

CWE-20

CWE-787

canonical

www.cve.org

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

8.4 High

AI Score

Confidence

High

0.002 Low

EPSS

Percentile

57.3%

JSON

The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the Linux kernel did not properly update 32-bit bounds, which could be turned into out of bounds reads and writes in the Linux kernel and therefore, arbitrary code execution. This issue was fixed via commit 049c4e13714e (“bpf: Fix alu32 const subreg bound tracking on bitwise operations”) (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. The AND/OR issues were introduced by commit 3f50f132d840 (“bpf: Verifier, do explicit ALU32 bounds tracking”) (5.7-rc1) and the XOR variant was introduced by 2921c90d4718 (“bpf:Fix a verifier failure with xor”) ( 5.10-rc1).

CNA 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"
      }
    ]
  }
]