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CVE-2021-3490

Severity
HIGH
CVSS
7.8
EPSS
0.27477
Risk score
40.82
CISA KEV
No
PoC
No
Published
2021-06-04
Modified
2024-09-16
First seen
2026-08-07
Aliases
EUVD-2021-26812, GHSA-9WFM-Q59X-QC3X
Products
n/a:Linux kernel linux-5.10.y <v5.10.37, n/a:Linux kernel linux-5.11.y <v5.11.21, n/a:Linux kernel linux-5.12.y <v5.12.4, n/a:Linux kernel trunk <v5.13-rc4, n/a:Linux kernel v5.7-rc1 <5.7*
Sources
euvd EUVD-2021-26812

Description

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).

References