Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-38166

CVE-2021-38166HIGH

n/a n/a — In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are p…

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  H  H    7.8   .0032   23.1     —

AFFECTED
  Product  Versions  Fixed
  n/a      n/a –     —

TIMELINE
  Aug 7   Reserved by mitre
  Aug 7   Published (CNA: mitre)
  Oct 8   ENRICHED — CVE-2021-38166. Received CVSS 7.8 and CPE data from NVD.

CWE-190, CWE-787 · CNA: mitre · CVSS v3.1 · 6 references · NVD status: Analyzed

Description

In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without the CAP_SYS_ADMIN capability.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 7, 2021	Reserved	Reserved by mitre
August 7, 2021	Published	Published (CNA: mitre)
October 8, 2026	ENRICHED	ENRICHED — CVE-2021-38166. Received CVSS 7.8 and CPE data from NVD.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	n/a	—	n/a	—

Weaknesses

CWE-190 · CWE-787

References (6)

https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=c4eb1f403243fc7bbb7de644db8587c03de36da6 [Patch, Vendor Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GUVLBJKZMWA3E3YXSH4SZ7BOYGJP4GXP/ [Third Party Advisory]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UL6CH5M5PRLMA3KPBX4LPUO6Z73GRISO/ [Third Party Advisory]
https://lore.kernel.org/bpf/20210806150419.109658-1-th.yasumatsu%40gmail.com/ [Patch]
https://security.netapp.com/advisory/ntap-20210909-0001/ [Third Party Advisory]
https://www.debian.org/security/2021/dsa-4978 [Third Party Advisory]

Authoritative record: CVE-2021-38166 at cve.org

Weaknesses: CWE-190 · CWE-787

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-38166 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.