---
id: CVE-2026-55894
title: Capstone is a disassembly framework
summary: >-
  Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone's
  arch/SH/SHDisassembler.c sh_disassemble() function computes an idx value from
  a raw 16-bit instruction without ensuring it is within the active
  mode-specific de…
severity: medium
cwe:
  - CWE-125
published: '2026-08-20'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T20:09:01.757'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55894'
references:
  - url: >-
      https://github.com/capstone-engine/capstone/commit/09e76802380b9e94d9720c44458d9d5282219e7e
    label: security-advisories@github.com
  - url: >-
      https://github.com/capstone-engine/capstone/commit/e17ee44a8307ea33375b4727ac4f987650bf7bed
    label: security-advisories@github.com
  - url: 'https://github.com/capstone-engine/capstone/pull/2968'
    label: security-advisories@github.com
  - url: 'https://github.com/capstone-engine/capstone/pull/2969'
    label: security-advisories@github.com
  - url: 'https://github.com/capstone-engine/capstone/releases/tag/6.0.0-Alpha10'
    label: security-advisories@github.com
  - url: >-
      https://github.com/capstone-engine/capstone/security/advisories/GHSA-gf2c-xwcp-hvf4
    label: security-advisories@github.com
  - url: >-
      https://github.com/capstone-engine/capstone/security/advisories/GHSA-gf2c-xwcp-hvf4
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55894.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-55894'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2520820'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-55894'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55894'
  - url: 'https://access.redhat.com/errata/RHSA-2026:59419'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00194
epssPercentile: 0.08985
ingestedAt: '2026-09-18T20:51:25.650Z'
vendor: Red Hat
product: Red Hat Hardened Images
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - openshift_container_platform 4
  - hardened_images
patched:
  - hardened_images
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: vendor
---

## Overview

Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone's arch/SH/SHDisassembler.c sh_disassemble() function computes an idx value from a raw 16-bit instruction without ensuring it is within the active mode-specific decode[] function-pointer table. An application using CS_ARCH_SH with CS_MODE_SH2A or CS_MODE_SH4A and CS_MODE_SHFPU can pass crafted bytecode through cs_disasm_iter() or cs_disasm(), causing the decode[idx] test to read outside the table and terminate the process with a segmentation fault. No code execution or information disclosure was demonstrated. This issue is fixed in version 6.0.0-Alpha10.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:59419** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59419)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55894.json)