CVE-2026-55893Public exploit

Heap overflow via unchecked SH operand append

Published Aug 20, 2026 · Updated Aug 20, 2026

Heap-based buffer overflow in Capstone before 6.0.0-Alpha10 allows attackers to crash or corrupt memory via crafted SH FPU bytecode. In arch/SH/SHDisassembler.c, SH floating-point decoders such as opFADD and opFMUL append operands through set_reg() and set_reg_n() using sh_info.op.op_count as an array index without checking the fixed-size operands[] array, leading to a four-byte write past the 176-byte sh_info allocation. Reachability requires an application to disassemble untrusted SuperH code with CS_ARCH_SH, SH2A or SH4A plus SHFPU, and CS_OPT_DETAIL enabled; demonstrated impact is process crash, with code execution dependent on heap layout.

CVSS severity7.3
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Capstone before 6.0.0-Alpha10 allows attackers to crash or corrupt memory via crafted SH FPU bytecode. In arch/SH/SHDisassembler.c, SH floating-point decoders such as opFADD and opFMUL append operands through set_reg() and set_reg_n() using sh_info.op.op_count as an array index without checking the fixed-size operands[] array, leading to a four-byte write past the 176-byte sh_info allocation. Reachability requires an application to disassemble untrusted SuperH code with CS_ARCH_SH, SH2A or SH4A plus SHFPU, and CS_OPT_DETAIL enabled; demonstrated impact is process crash, with code execution dependent on heap layout.

The record

CVE
CVE-2026-55893
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
Capstone Engine
Product
Capstone
Classifications
CWE-122, T1203
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

7.3GitHub, Inc.CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-122Heap-based Buffer Overflow
T1203Exploitation for Client Execution

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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