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Vulnerability · Published Aug 20, 2026 · Assigned by GitHub_M

CVE-2026-55894Capstone SH disassembler `sh_disassemble` out-of-bounds read via crafted SH2A bytecode

Medium 6.8

In plain English

A medium-severity out-of-bounds read in capstone from capstone-engine. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 4.0)6.8Medium
Exploit odds (30 days)0.2%top 90.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone's arch/SH/SHDisassembler.c sh_disassemble() function computes an idx value from a raw 16-bit instruction without ensuring it is within the active mode-specific decode[] function-pointer table. An application using CS_ARCH_SH with CS_MODE_SH2A or CS_MODE_SH4A and CS_MODE_SHFPU can pass crafted bytecode through cs_disasm_iter() or cs_disasm(), causing the decode[idx] test to read outside the table and terminate the process with a segmentation fault. No code execution or information disclosure was demonstrated. This issue is fixed in version 6.0.0-Alpha10.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12capstoneno fix listedDEBIAN-CVE-2026-55894
Debian:13capstoneno fix listedDEBIAN-CVE-2026-55894
Debian:14capstoneno fix listedDEBIAN-CVE-2026-55894
Ubuntu:22.04:LTScapstoneno fix listedUBUNTU-CVE-2026-55894
Ubuntu:24.04:LTScapstoneno fix listedUBUNTU-CVE-2026-55894
Ubuntu:26.04:LTScapstoneno fix listedUBUNTU-CVE-2026-55894
Ubuntu:26.10capstoneno fix listedUBUNTU-CVE-2026-55894

Affected products (as reported)

VendorProductVersions
capstone-engine capstone < 6.0.0-Alpha10

Weakness: CWE-125 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References