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TI-2026-40344 Aliases CVE-2026-55893

Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode

Priority LOW 33CWE-122Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Passive
Attack complexity
High
Attack requirements
Present
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 1 fixed, 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00186 8th percentileScored 2026-11-07
Fix Partial capstone (capstone-engine): 6.0.0-Alpha10Red Hat: 1 advisoryRed Hat: 1 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
capstone-enginecapstonebefore 6.0.0-Alpha106.0.0-Alpha10Patch availableCNA
  • capstone Vendorcapstone-engine Affected before 6.0.0-Alpha10 Fixed in 6.0.0-Alpha10 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:capstone-engine:capstone:*:*:*:*:*:*:*:*——capstone-engine
  • cpe:2.3:a:capstone-engine:capstone:*:*:*:*:*:*:*:* Versions — — ·capstone-engine

Remediation

  • Fix · CNA capstone (capstone-engine) Fixed in 6.0.0-Alpha10

Red Hat 1 advisory

  • RHSA-2026:59419 Released 2026-08-25 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images capstone-5.0.8-0.3.hum1@aarch64, capstone-5.0.8-0.3.hum1@src, capstone-5.0.8-0.3.hum1@x86_64 +8

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Red Hat Hardened ImagesFixed RHSA-2026:59419

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55893
  2. 2026-11-01 Affected versions changed · Red Hat

References

Other 6

  • TI-2025-41703 Capstone doesn't check vsnprintf return in SStream_concat, allows stack buffer underflow and overflow CVSS 3.1CRITICAL 9.8
  • TI-2025-41500 Capstone doesn't check Skipdata length, leading to cs_insn.bytes heap buffer overflow CVSS 3.1HIGH 7.8
  • TI-2026-40345 Capstone SH disassembler `sh_disassemble` out-of-bounds read via crafted SH2A bytecode CVSS 4.0MEDIUM 6.8
  • TI-2026-34733 Capstone has a NULL Pointer Dereference with 3DNow! opcodes CVSS 3.1MEDIUM 5.9
  • TI-2026-36469 Capstone M68K and RISCV `cs_insn_name()` invalid IDs can trigger out-of-bounds reads and process crashes CVSS 3.1MEDIUM 5.1
  • TI-2026-36458 Capstone WASM `br_table` instruction-size truncation can cause no-progress disassembly and parser desynchronization CVSS 4.0LOW 2.0
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences