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CVE-2026-47143 capstone-engine CVE debrief

A NULL pointer dereference vulnerability exists in the Capstone disassembly framework, affecting versions prior to 6.0.0-Alpha8 and 5.0.8. The vulnerability occurs in the `modRMRequired()` and `decode()` functions when disassembling 3DNow! opcodes (`0F 0F`). A remote attacker can crash any application using the reduced X86 Capstone library by supplying a crafted input containing the 4-byte sequence `0F 0F <modrm> <imm8>`. This vulnerability can be mitigated by updating to version 6.0.0-Alpha8 or 5.0.8 or later, using compensating controls such as input validation and sanitization, and monitoring for and responding to potential attacks.

Vendor
capstone-engine
Product
capstone
CVSS
MEDIUM 5.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-21
Original CVE updated
2026-07-22
Advisory published
2026-07-21
Advisory updated
2026-07-22

Who should care

Developers and users of the Capstone disassembly framework, particularly those using versions prior to 6.0.0-Alpha8 and 5.0.8, should be aware of this vulnerability and take steps to mitigate it. This includes updating to version 6.0.0-Alpha8 or 5.0.8 or later, using compensating controls such as input validation and sanitization, and monitoring for and responding to potential attacks.

Technical summary

The vulnerability is caused by a NULL pointer dereference in the `modRMRequired()` and `decode()` functions when disassembling 3DNow! opcodes (`0F 0F`). This occurs in builds compiled with `-DCAPSTONE_X86_REDUCE`. An attacker can exploit this vulnerability by supplying a crafted input containing the 4-byte sequence `0F 0F <modrm> <imm8>`, which can crash any application using the reduced X86 Capstone library. The vulnerability affects versions prior to 6.0.0-Alpha8 and 5.0.8 of the Capstone disassembly framework.

Defensive priority

Medium

Recommended defensive actions

  • Update to version 6.0.0-Alpha8 or 5.0.8 or later
  • Use a compensating control, such as input validation and sanitization
  • Monitor for and respond to potential attacks
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-21T21:16:50.270Z and was last modified on 2026-07-22T14:17:19.527Z. The NVD entry is currently MEDIUM. The vulnerability affects versions prior to 6.0.0-Alpha8 and 5.0.8 of the Capstone disassembly framework. The vulnerability occurs in the `modRMRequired()` and `decode()` functions when disassembling 3DNow! opcodes (`0F 0F`). A remote attacker can crash any application using the reduced X86 Capstone library by supplying a crafted input containing the 4-byte sequence `0F 0F <modrm> <imm8>`.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-47143 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-47143

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-47143 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-47143

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.