CVE-2021-3489Linux kernel eBPF RINGBUF map oversized allocation
- 7.8HighCVSS base score
- 0.55%Exploitation in 30 daysEPSS · top 53% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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).
Timeline
ID reserved
By canonical
- 56 days later
· 56 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| canonicalCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.55% · top 53% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected trunk – < v5.13-rc4
- affected linux-5.12.y – < v5.12.4
- affected linux-5.11.y – < v5.11.21
- affected linux-5.10.y – < v5.10.37
- affected v5.8 – < 5.8*
References
References6
- [oss-security] CVE-2021-3489 - Linux kernel eBPF RINGBUF map oversized allocation (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=4b81ccebaeee885ab1aa1438133f2991e3a2b6ea (opens in a new tab)x_refsource_MISCx_transferred
- https://www.zerodayinitiative.com/advisories/ZDI-21-590/ (opens in a new tab)x_refsource_MISCx_transferred
- https://ubuntu.com/security/notices/USN-4950-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- https://ubuntu.com/security/notices/USN-4949-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- https://security.netapp.com/advisory/ntap-20210716-0004/ (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-26811 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-3489)Record last updated .