High severity · published Aug 20, 2026
CVE-2026-55893
Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
7.3
CVSS
0.2%
EPSS
No
On KEV
Description
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CA
capstone · capstone-engine
< 6.0.0-Alpha10 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55893
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55893
github.com
https://github.com/capstone-engine/capstone/commit/09e76802380b9e94d9720c44458d9d5282219e7e
github.com
https://github.com/capstone-engine/capstone/commit/e17ee44a8307ea33375b4727ac4f987650bf7bed
github.com
https://github.com/capstone-engine/capstone/pull/2968
github.com
https://github.com/capstone-engine/capstone/pull/2969
github.com
https://github.com/capstone-engine/capstone/releases/tag/6.0.0-Alpha10
github.com
https://github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh
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