Disassembly hang via WASM instruction-size truncation
Published Aug 14, 2026 · Updated Aug 14, 2026
Numeric truncation in Capstone before 6.0.0-Alpha9 allows attackers to hang disassembly or corrupt parser output via a crafted br_table. Capstone's read_brtable parser accumulates the encoded br_table length in a wide temporary but returns it through a 16-bit instruction-size output, wrapping 65,536 bytes to zero and underreporting larger sizes. An attacker must cause an application to pass a large, well-formed br_table to cs_disasm() or cs_disasm_iter(); unbounded decoding can exhaust process resources.
Summary
What happened
Numeric truncation in Capstone before 6.0.0-Alpha9 allows attackers to hang disassembly or corrupt parser output via a crafted br_table. Capstone's read_brtable parser accumulates the encoded br_table length in a wide temporary but returns it through a 16-bit instruction-size output, wrapping 65,536 bytes to zero and underreporting larger sizes. An attacker must cause an application to pass a large, well-formed br_table to cs_disasm() or cs_disasm_iter(); unbounded decoding can exhaust process resources.
The record
- CVE
- CVE-2026-49263
- Published
- Aug 14, 2026
- Updated
- Aug 14, 2026
- Vendor
- Capstone Engine
- Product
- Capstone
- Classifications
- CWE-197, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 14, 2026CVE publishedPublication date reported by the CVE source.
- Aug 14, 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.
- Affected versionversion=< 6.0.0-Alpha9
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Bounded WASM br_table proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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