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Vulnerability record · CVE-2021-3490 · published 4 June 2021

CVE-2021-3490: Linux kernel improper input validation vulnerability

Linux · Linux Kernel

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).

7.8 CVSS 3.1 High EPSS 27% · top 2.0% CWE-20 · Improper input validationCWE-787 · Out-of-bounds write
7.8CVSS 3.1 base score, v2 7.2
27%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
14References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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).

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

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/164015/Linux-eBPF-ALU32-32-bit-Invalid-Bounds-Tracking-Local-Privilege-Escalation.h ExploitThird Party AdvisoryVDB Entry
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e13714ecbca567b4d5f6d563f05d431c80e PatchVendor Advisory
https://security.netapp.com/advisory/ntap-20210716-0004/ Third Party Advisory
https://ubuntu.com/security/notices/USN-4949-1 Third Party Advisory
https://ubuntu.com/security/notices/USN-4950-1 Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/05/11/11 Mailing ListPatchThird Party Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-606/ Third Party AdvisoryVDB Entry
http://packetstormsecurity.com/files/164015/Linux-eBPF-ALU32-32-bit-Invalid-Bounds-Tracking-Local-Privilege-Escalation.h ExploitThird Party AdvisoryVDB Entry
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e13714ecbca567b4d5f6d563f05d431c80e PatchVendor Advisory
https://security.netapp.com/advisory/ntap-20210716-0004/ Third Party Advisory
https://ubuntu.com/security/notices/USN-4949-1 Third Party Advisory
https://ubuntu.com/security/notices/USN-4950-1 Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/05/11/11 Mailing ListPatchThird Party Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-606/ Third Party AdvisoryVDB Entry

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Source: NIST National Vulnerability Database (record CVE-2021-3490), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.