CVE-2021-3490
HighThe 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 score
7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness type
CWE-20CVE-2021-3490 is a Improper Input Validation vulnerability
What is Improper Input Validation?
The product receives input but does not validate it correctly, allowing attackers to craft inputs that cause unexpected behavior. Learn more on MITRE CWE
References
The following references provide additional information about CVE-2021-3490 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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Exploit Third Party Advisory VDB Entry
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Third Party Advisory
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Ubuntu Securityhttps://ubuntu.com/security/notices/USN-4949-1Third Party Advisory
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Ubuntu Securityhttps://ubuntu.com/security/notices/USN-4950-1Third Party Advisory
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Zerodayinitiativehttps://www.zerodayinitiative.com/advisories/ZDI-21-606/Third Party Advisory VDB Entry
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PatchKernel patch commithttps://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e13714ecbca567b4d5f6d563f05d431c80e
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PatchKernel patch commithttps://www.openwall.com/lists/oss-security/2021/05/11/11
Frequently asked questions
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What is CVE-2021-3490?
CVE-2021-3490 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Improper Input Validation flaw (CWE-20) . CVE-2021-3490 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2021-3490?
CVE-2021-3490 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. -
Is there a patch available for CVE-2021-3490?
No patch is currently available for CVE-2021-3490. Monitor the NIST NVD and your Linux distribution's security advisories for updates.
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Is CVE-2021-3490 actively exploited?
No — CVE-2021-3490 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is Improper Input Validation (CWE-20)?
The product receives input but does not validate it correctly, allowing attackers to craft inputs that cause unexpected behavior. View CWE-20 on MITRE CWE →