Vulnerability 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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.10, < 5.10.37 |
| Canonical | Ubuntu Linux | 20.04 |
Related Weaknesses (CWE)
References
- http://packetstormsecurity.com/files/164015/Linux-eBPF-ALU32-32-bit-Invalid-BounExploitThird Party AdvisoryVDB Entry
- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e137PatchVendor Advisory
- https://security.netapp.com/advisory/ntap-20210716-0004/Third Party Advisory
- https://ubuntu.com/security/notices/USN-4949-1Third Party Advisory
- https://ubuntu.com/security/notices/USN-4950-1Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/05/11/11Mailing 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-BounExploitThird Party AdvisoryVDB Entry
- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e137PatchVendor Advisory
- https://security.netapp.com/advisory/ntap-20210716-0004/Third Party Advisory
- https://ubuntu.com/security/notices/USN-4949-1Third Party Advisory
- https://ubuntu.com/security/notices/USN-4950-1Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/05/11/11Mailing ListPatchThird Party Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-606/Third Party AdvisoryVDB Entry
FAQ
What is CVE-2021-3490?
CVE-2021-3490 is a vulnerability with a CVSS score of 7.8 (HIGH). 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 kerne...
How severe is CVE-2021-3490?
CVE-2021-3490 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-3490?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel, Canonical Ubuntu Linux.