CVE-2021-45402 - Vulnerability Details - OpenCVE

The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through v5.16-rc5 did not properly update bounds while handling the mov32 instruction, which allows local users to obtain potentially sensitive address information, aka a "pointer leak."

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

Access Vector Local

Access Complexity Low

Authentication None

Confidentiality Impact Partial

Integrity Impact None

Availability Impact None

This CVE is not in the KEV list.

Exploitation none

Automatable no

Technical Impact partial

Vendors	Products
Linux	Linux Kernel

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:5.16:rc1::::::
	cpe:2.3:o:linux:linux_kernel:5.16:rc2::::::
	cpe:2.3:o:linux:linux_kernel:5.16:rc3::::::
	cpe:2.3:o:linux:linux_kernel:5.16:rc4::::::
	cpe:2.3:o:linux:linux_kernel:5.16:rc5::::::

No data.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=3cf2b61eb06765e27fec6799292d9fb46d0b7e60
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b1a7288dedc6caf9023f2676b4f5ed34cf0d4029
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=e572ff80f05c33cd0cb4860f864f5c9c044280b6
https://nvd.nist.gov/vuln/detail/CVE-2021-45402
https://www.cve.org/CVERecord?id=CVE-2021-45402

History

Thu, 08 Oct 2026 22:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

MITRE

Status: PUBLISHED

Assigner: mitre

Published: 2022-02-11T14:36:29.000Z

Updated: 2026-10-08T21:03:11.802Z

Reserved: 2021-12-20T00:00:00.000Z

Link: CVE-2021-45402

Vulnrichment

Updated: 2024-08-04T04:39:20.900Z

NVD

Status : Modified

Published: 2022-02-11T15:15:07.687

Modified: 2026-10-08T21:17:42.407

Link: CVE-2021-45402

Redhat

Severity : Low

Publid Date: 2022-02-11T00:00:00Z

Links: CVE-2021-45402 - Bugzilla

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{"bugzilla": {"description": "kernel: pointer leak in check_alu_op() of kernel/bpf/verifier.c", "id": "2054865", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2054865"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N", "status": "draft"}, "cwe": "CWE-120", "details": ["The check_alu_op() function in kernel/bpf/verifier.c in the Linux kernel through v5.16-rc5 did not properly update bounds while handling the mov32 instruction, which allows local users to obtain potentially sensitive address information, aka a \"pointer leak.\"", "A memory leak flaw was found in the Linux kernel\u2019s BPF subsystem in the way a user triggers the check_alu_op function of the BPF verifier. This flaw allows a local user to obtain unauthorized memory access or potentially crash the system."], "mitigation": {"lang": "en:us", "value": "The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.\nFor the Red Hat Enterprise Linux 7, the eBPF for unprivileged users is always disabled.\nFor the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command:\n# cat /proc/sys/kernel/unprivileged_bpf_disabled\nThe setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw."}, "name": "CVE-2021-45402", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-alt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2022-02-11T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-45402\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-45402\nhttps://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=3cf2b61eb06765e27fec6799292d9fb46d0b7e60\nhttps://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b1a7288dedc6caf9023f2676b4f5ed34cf0d4029\nhttps://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=e572ff80f05c33cd0cb4860f864f5c9c044280b6"], "threat_severity": "Low"}