{"cve":"CVE-2021-3489","nvd":{"published":"2021-06-04T02:15:07.047","modified":"2026-06-17T04:05:11.590","status":"Modified","description":"The eBPF RINGBUF bpf_ringbuf_reserve() function in the Linux kernel did not check that the allocated size was smaller than the ringbuf size, allowing an attacker to perform out-of-bounds writes within the kernel and therefore, arbitrary code execution. This issue was fixed via commit 4b81ccebaeee (\"bpf, ringbuf: Deny reserve of buffers larger than ringbuf\") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced via 457f44363a88 (\"bpf: Implement BPF ring buffer and verifier support for it\") (v5.8-rc1).","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-787","CWE-119"],"references":["https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6ea","https://security.netapp.com/advisory/ntap-20210716-0004/","https://ubuntu.com/security/notices/USN-4949-1","https://ubuntu.com/security/notices/USN-4950-1","https://www.openwall.com/lists/oss-security/2021/05/11/10"],"products":["canonical:ubuntu_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-3489","score":0.0055,"percentile":0.46004,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}