CVE-2021-3490

Summary

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).

Affected Software

VendorProductVersion RangeStatus
LinuxLinux kerneltrunk < v5.13-rc4affected
LinuxLinux kernellinux-5.12.y < v5.12.4affected
LinuxLinux kernellinux-5.11.y < v5.11.21affected
LinuxLinux kernellinux-5.10.y < v5.10.37affected
LinuxLinux kernelv5.7-rc1 < 5.7*affected

Weaknesses

  • CWE-787: CWE-787 Out-of-bounds Write
  • CWE-20: CWE-20 Improper Input Validation

ADP Enrichment

CVE Program Container

Additional References

References