SB2026102265 - Out-of-bounds write in Linux kernel ipv4

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Main Vulnerability Database SB2026102265

SB2026102265 - Out-of-bounds write in Linux kernel ipv4

Published: October 22, 2026

Security Bulletin ID SB2026102265
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Out-of-bounds write (CVE-ID: CVE-2026-98493)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local privileged user to cause a denial of service during Linux kernel boot.

The vulnerability exists due to an out-of-bounds write in ic_dhcp_init_options() in net/ipv4/ipconfig.c when constructing boot-time DHCP options without checking the space remaining for hostname and vendor-class values. A local privileged user can supply a combination of hostname and dhcpclass= values that exceeds the fixed 312-byte bootp_pkt.exten[] buffer to overwrite adjacent memory and disrupt boot, including triggering a kernel panic when CONFIG_FORTIFY_SOURCE and panic_on_warn=1 are enabled.


Remediation

Install update from vendor's website.

References