CVE-2026-55893: CWE-122: Heap-based Buffer Overflow in capstone-engine capstone
Description
A heap-based buffer overflow vulnerability exists in capstone-engine versions prior to 6.0.0-Alpha10 in the SH floating-point decoders. The issue arises when crafted instructions cause the operand count to exceed the allocated buffer size, leading to a four-byte overflow. This can crash the process and potentially allow code execution depending on heap layout. The vulnerability is fixed in version 6.0.0-Alpha10.
CVSS v4.0
Score 7.3high
Affected software
capstone-engine
capstone
pkg:github/capstone-engine/capstoneRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Capstone-engine versions 6.0.0-Alpha9 and earlier contain a heap-based buffer overflow in the SH floating-point decoders (opFADD, opFMUL, opFSUB) within arch/SH/SHDisassembler.c. These decoders call set_reg() and set_reg_n() using sh_info.op.op_count without validating against the fixed-size operands[] array. When processing crafted instructions via cs_disasm_iter() or cs_disasm() with CS_ARCH_SH and specific modes (CS_MODE_SH2A, CS_MODE_SH4A, CS_MODE_SHFPU) and the CS_OPT_DETAIL option, the operand count can increment beyond the 176-byte allocation, causing a four-byte heap buffer overflow write. This corruption can crash the process and may enable code execution depending on heap layout. The issue is resolved in version 6.0.0-Alpha10.
Potential Impact
Exploitation of this vulnerability can lead to process crashes and potentially arbitrary code execution depending on the heap layout. The vulnerability affects local users who can supply crafted instructions to the disassembler. The CVSS 4.0 score is 7.3 (high severity), reflecting the complexity and potential impact.
Mitigation Recommendations
Upgrade to capstone-engine version 6.0.0-Alpha10 or later, where this heap-based buffer overflow vulnerability has been fixed. No other mitigations are specified or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-17T16:59:42.760Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a87778eacd9273b492c5fab
Added to database: 08/20/2026, 21:54:22 UTC
Last enriched: 09/10/2026, 20:46:55 UTC
Last updated: 10/04/2026, 18:55:09 UTC
Views: 89
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.