SB20260720364 - Heap-based buffer overflow in Linux kernel target iscsi driver

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Main Vulnerability Database SB20260720364

SB20260720364 - Heap-based buffer overflow in Linux kernel target iscsi driver

Published: July 20, 2026

Security Bulletin ID SB20260720364
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Heap-based buffer overflow (CVE-ID: CVE-2026-63886)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to a heap-based buffer overflow in chap_server_compute_hash() in the iSCSI target CHAP authentication handling when processing a specially crafted base64-encoded CHAP_R response. A remote user can send a specially crafted CHAP authentication response to cause a denial of service.

The issue affects the BASE64 CHAP_R decoding path; the mutual CHAP CHAP_C decoding path is not affected.


Remediation

Install update from vendor's website.

References