Buffer overflow in Linux Kernel
CVE-2021-3490
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).
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.275 (97.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Linux Kernel — versions trunk, linux-5.12.y, linux-5.11.y
- Linux Linux_kernel — versions 5.13
- Canonical Ubuntu_linux — versions 20.04, 20.10, 21.04
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@ubuntu.com (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- security@ubuntu.com (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- security@ubuntu.com (mailing-list, x_refsource_MLIST, Patch, Mailing List, Third Party Advisory)
- security@ubuntu.com (Patch, x_refsource_MISC, Vendor Advisory)
- security@ubuntu.com (VDB Entry, Third Party Advisory, x_refsource_MISC)
- security@ubuntu.com (x_refsource_CONFIRM, Third Party Advisory)
- security@ubuntu.com (Exploit, VDB Entry, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-3490?
- CVE-2021-3490 is a high-severity vulnerability in Linux Kernel, classified under Improper Input Validation. CVSS score: 7.8/10. Published 2021-06-04.
- How severe is CVE-2021-3490?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2021-3490 known to be exploited?
- 68 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.