CVE-2026-49263
Published:August 14, 2026
Updated:August 31, 2026
Capstone is a disassembly framework. Prior to version 6.0.0-Alpha9, Capstone's WebAssembly backend accepts attacker-controlled raw WASM instruction bytes through the public "cs_disasm()" and "cs_disasm_iter()" APIs. For a large but well-formed "br_table" instruction, the WASM decoder accumulates the immediate length in a wider local variable but returns it through a "uint16_t" instruction-size path. When the encoded instruction length is exactly 65,536 bytes, the size wraps to zero and "cs_disasm()" can repeatedly decode the same instruction without advancing. For larger lengths, "cs_disasm_iter()" advances into the middle of the "br_table" payload and decodes target bytes as subsequent instructions. This is an availability and parser-integrity issue. Version 6.0.0-Alpha9 patches the issue.
Affected Packages
https://github.com/capstone-engine/capstone.git (GITHUB):
Affected version(s) >=1.0 <6.0.0-Alpha9Fix Suggestion:
Update to version 6.0.0-Alpha9Related Resources (4)
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Contact UsCVSS v4
Base Score:
2
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.4
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Weakness Type (CWE)
Numeric Truncation Error
EPSS
Base Score:
0.13