Local privilege escalation via incorrect ALU32 bounds
Published Jun 4, 2021 · Updated Sep 16, 2024
Out-of-bounds access in the Linux kernel eBPF verifier allows local users to execute arbitrary kernel code through crafted programs. For AND, OR, and XOR instructions, the verifier fails to update 32-bit subregister bounds after constant operations, permitting verifier-approved out-of-bounds reads and writes. Exploitation requires low-privileged local access and unprivileged eBPF availability; successful writes can elevate the process to root.
Summary
What happened
Out-of-bounds access in the Linux kernel eBPF verifier allows local users to execute arbitrary kernel code through crafted programs. For AND, OR, and XOR instructions, the verifier fails to update 32-bit subregister bounds after constant operations, permitting verifier-approved out-of-bounds reads and writes. Exploitation requires low-privileged local access and unprivileged eBPF availability; successful writes can elevate the process to root.
The record
- CVE
- CVE-2021-3490
- Published
- Jun 4, 2021
- Updated
- Sep 16, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-20, CWE-125, CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 4, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=linux-5.10.y <v5.10.37
- Affected versionversion=linux-5.11.y <v5.11.21
- Affected versionversion=linux-5.12.y <v5.12.4
- Affected versionversion=trunk <v5.13-rc4
- Affected versionversion=v5.7-rc1 <5.7*
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Linux eBPF ALU32 32-bit Invalid Bounds Tracking LPEweaponized · validated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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