CVE-2026-55893 (GCVE-0-2026-55893)
Vulnerability from cvelistv5 – Published: 2026-08-20 21:32 – Updated: 2026-08-21 21:45
VLAI
EPSS
VEX
Title
Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
Summary
Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone's arch/SH/SHDisassembler.c SH floating-point decoders such as opFADD, opFMUL, and opFSUB call set_reg() and set_reg_n() using sh_info.op.op_count without checking the fixed-size operands[] array. Repeated crafted instructions processed through cs_disasm_iter() or cs_disasm() with CS_ARCH_SH, CS_MODE_SH2A or CS_MODE_SH4A, CS_MODE_SHFPU, and CS_OPT_DETAIL can increment the operand count beyond the 176-byte sh_info allocation and perform a four-byte heap buffer overflow write. The corruption can crash the process and may enable code execution depending on heap layout. This issue is fixed in version 6.0.0-Alpha10.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-21 21:00 UTC
CWE
- CWE-122 - Heap-based Buffer Overflow
Assigner
References
6 references
| URL | Tags |
|---|---|
| https://github.com/capstone-engine/capstone/secur… | x_refsource_CONFIRM |
| https://github.com/capstone-engine/capstone/pull/2968 | x_refsource_MISC |
| https://github.com/capstone-engine/capstone/pull/2969 | x_refsource_MISC |
| https://github.com/capstone-engine/capstone/commi… | x_refsource_MISC |
| https://github.com/capstone-engine/capstone/commi… | x_refsource_MISC |
| https://github.com/capstone-engine/capstone/relea… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| capstone-engine | capstone |
Affected:
< 6.0.0-Alpha10
|
guessed |
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}
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"source": {
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"discovery": "UNKNOWN"
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"title": "Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode"
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"datePublished": "2026-08-20T21:32:46.718Z",
"dateReserved": "2026-06-17T16:59:42.760Z",
"dateUpdated": "2026-08-21T21:45:29.340Z",
"state": "PUBLISHED"
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"date": "2026-10-22",
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"percentile": "0.07794"
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"microsoft_vex": {
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"cve": "CVE-2026-55893",
"id": "msrc_CVE-2026-55893",
"initial_release_date": "2026-08-25T01:03:03.000Z",
"product_status:known_affected": "1",
"product_status:known_not_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-55893.json",
"version": "2"
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"vendor": "capstone-engine",
"versions": [
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"status": "affected",
"version": "\u003c 6.0.0-Alpha10"
}
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"source": "security-advisories@github.com"
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"descriptions": [
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"value": "Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone\u0027s arch/SH/SHDisassembler.c SH floating-point decoders such as opFADD, opFMUL, and opFSUB call set_reg() and set_reg_n() using sh_info.op.op_count without checking the fixed-size operands[] array. Repeated crafted instructions processed through cs_disasm_iter() or cs_disasm() with CS_ARCH_SH, CS_MODE_SH2A or CS_MODE_SH4A, CS_MODE_SHFPU, and CS_OPT_DETAIL can increment the operand count beyond the 176-byte sh_info allocation and perform a four-byte heap buffer overflow write. The corruption can crash the process and may enable code execution depending on heap layout. This issue is fixed in version 6.0.0-Alpha10."
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"value": "Capstone es un framework de desensamblado. En 6.0.0-Alpha9 y anteriores, los decodificadores de punto flotante SH de arch/SH/SHDisassembler.c de Capstone, como opFADD, opFMUL y opFSUB, llaman a set_reg() y set_reg_n() usando sh_info.op.op_count sin verificar el array de tama\u00f1o fijo operands[]. Instrucciones manipuladas repetidas procesadas a trav\u00e9s de cs_disasm_iter() o cs_disasm() con CS_ARCH_SH, CS_MODE_SH2A o CS_MODE_SH4A, CS_MODE_SHFPU y CS_OPT_DETAIL pueden incrementar el contador de operandos m\u00e1s all\u00e1 de la asignaci\u00f3n sh_info de 176 bytes y realizar una escritura de desbordamiento de b\u00fafer de pila (heap) de cuatro bytes. La corrupci\u00f3n puede bloquear el proceso y puede permitir la ejecuci\u00f3n de c\u00f3digo dependiendo del dise\u00f1o de la pila (heap). Este problema est\u00e1 solucionado en la versi\u00f3n 6.0.0-Alpha10."
}
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"lastModified": "2026-10-18T20:10:00.110",
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"modifiedSubAvailabilityImpact": "NOT_DEFINED",
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"valueDensity": "NOT_DEFINED",
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"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-55893.json",
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}
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