Bug 2520815 (CVE-2026-55893)

Summary:	CVE-2026-55893 capstone: Capstone: Heap buffer overflow with potential code execution
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Capstone, a disassembly framework. The SH floating-point decoders in `arch/SH/SHDisassembler.c` do not correctly validate the size of the `operands[]` array when processing certain instructions. This vulnerability allows a local attacker to provide specially crafted SH2A FPU bytecode, leading to a heap buffer overflow. Successful exploitation can cause the application to crash, resulting in a Denial of Service (DoS), and may potentially enable arbitrary code execution.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2523324, 2523325, 2523326, 2523327, 2523328, 2523329
Bug Blocks:

Description OSIDB Bzimport 2026-08-20 21:51:26 UTC

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.