CVE-2026-55894Public exploit

Process crash via unchecked SH decode index

Published Aug 20, 2026 · Updated Aug 20, 2026

Out-of-bounds read in Capstone before 6.0.0-Alpha10 allows attackers to crash applications via crafted SH2A or SH4A bytecode. In arch/SH/SHDisassembler.c, sh_disassemble() derives idx from a raw 16-bit instruction and tests decode[idx] without verifying that the index is valid for the active mode-specific function-pointer table. Reachability requires an application to expose cs_disasm() or cs_disasm_iter() on untrusted input with CS_ARCH_SH and SH2A or SH4A plus SHFPU enabled; published material demonstrates a segmentation fault, not code execution or data disclosure.

CVSS severity6.8
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Capstone before 6.0.0-Alpha10 allows attackers to crash applications via crafted SH2A or SH4A bytecode. In arch/SH/SHDisassembler.c, sh_disassemble() derives idx from a raw 16-bit instruction and tests decode[idx] without verifying that the index is valid for the active mode-specific function-pointer table. Reachability requires an application to expose cs_disasm() or cs_disasm_iter() on untrusted input with CS_ARCH_SH and SH2A or SH4A plus SHFPU enabled; published material demonstrates a segmentation fault, not code execution or data disclosure.

The record

CVE
CVE-2026-55894
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
Capstone Engine
Product
Capstone
Classifications
CWE-125, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.0.0-Alpha10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Capstone Engine · Capstoneversion=< 6.0.0-Alpha10

Published CVSS scores

6.8GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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