Capstone M68K and RISCV `cs_insn_name()` invalid IDs can trigger out-of-bounds reads and process crashes
Capstone is a disassembly framework. Prior to version 6.0.0-Alpha9, Capstone's public `cs_insn_name()` API forwards caller-supplied instruction IDs directly to the selected architecture backend. Most backends validate the ID before indexing instruction-name tables, but the M68K and RISCV backends have missing or incomplete bounds checks. On a Capstone handle opened for M68K or RISCV, a caller-controlled invalid instruction ID can trigger an out-of-bounds read and crash the process. The demonstrated impact is availability loss in applications or bindings that expose instruction-name lookup to untrusted IDs. No code execution or data disclosure was demonstrated. Version 6.0.0-Alpha9 patches the issue.
- Published
- Aug 14, 2026
- Updated
- Sep 18, 2026
- EPSS
- 0.2% · 6th percentile
- CWE
- CWE-125
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Report tools
Action score
20
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 5.1
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
capstone-engine capstone
- < 6.0.0-Alpha9affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | capstone | all versions | — |
Same product
capstone-engine: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-68114Capstone doesn't check vsnprintf return in SStream_concat, allows stack buffer underflow and overflow39Monitor
- CVE-2017-6952Integer overflow in the cs_winkernel_malloc function in winkernel_mm.c in Capstone 3.0.4 and earlier allows attackers to cause a denial of s35Monitor
- CVE-2025-67873Capstone doesn't check Skipdata length, leading to cs_insn.bytes heap buffer overflow31Monitor
- CVE-2026-55893Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode29Monitor
- CVE-2026-55894Capstone SH disassembler `sh_disassemble` out-of-bounds read via crafted SH2A bytecode27Monitor
- CVE-2026-47143Capstone has a NULL Pointer Dereference with 3DNow! opcodes23Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-558946 days apartCapstone SH disassembler `sh_disassemble` out-of-bounds read via crafted SH2A bytecode27Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- github.com/capstone-engine/capstone/blob/251c5bb4bc9bb92973e738ae3c5f4ef86f103356/ChangeLog#L102
- github.com/capstone-engine/capstone/security/advisories/GHSA-jrw4-wj52-2vw8
Vendor advisories and official records. Exploit/PoC links are deliberately left out.