---
id: CVE-2026-98591
title: 'kernel: bpf: Fix bounds check for skb-backed dynptrs (CVE-2026-98591)'
summary: >-
  A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem.
  An integer underflow in the bounds-checking logic for network packet buffer
  pointers allows validation checks to pass incorrectly. A local user capable of
  runni…
severity: medium
cvss: 6.7
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
cwe: CWE-191
vendor: Red Hat
product: Red Hat Enterprise Linux 10
affected:
  - enterprise_linux 10
published: '2026-10-18'
updated: '2026-10-20'
sourceUpdated: '2026-10-20T04:44:02+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-98591'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2554923'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-98591'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98591'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98591.mbox
  - url: 'https://git.kernel.org/stable/c/1b923538598be768e9f2f258a77a083d00e0c78b'
  - url: 'https://git.kernel.org/stable/c/37877a24758068742fef687a7cf5362360dde1d1'
  - url: 'https://git.kernel.org/stable/c/1196903a27cac5c929c7517e987a8d159f20c5e5'
  - url: 'https://git.kernel.org/stable/c/39ffceaddb10753eac12785dba6ac0673860b4ac'
  - url: 'https://git.kernel.org/stable/c/ed6eec97b534979dcf28b40c389cee57bd6561d4'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00201
epssPercentile: 0.09869
ingestedAt: '2026-10-18T15:45:12.250Z'
---

## Overview

A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. An integer underflow in the bounds-checking logic for network packet buffer pointers allows validation checks to pass incorrectly. A local user capable of running BPF programs could exploit this flaw to create pointers referencing invalid memory, potentially leading to out-of-bounds memory access, a denial of service (system crash), or privilege escalation.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98591.json)

**kernel: bpf: Fix bounds check for skb-backed dynptrs** — rated Moderate by Red Hat. Released 2026-10-18, updated 2026-10-20.

Affected:

- Red Hat Enterprise Linux 10

No fix planned:

- Red Hat Enterprise Linux 10

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Fix deferred