---
title: "CVE-2026-55893\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-55893?format=md
keywords: index, follow
---

# CVE-2026-55893

Publication date 20 August 2026

Last updated 2 September 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| capstone | 26.04 LTS resolute | Needs evaluation |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v4.0

**Base score**

7.3 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Local |
  | Attack complexity | High |
  | Attack requirements | Present |
  | Privileges required | None |
  | User interaction | Passive |
  | Vulnerable system - Confidentiality impact | High |
  | Vulnerable system - Integrity impact | High |
  | Vulnerable system - Availability impact | High |
  | Subsequent system - Confidentiality impact | None |
  | Subsequent system - Integrity impact | None |
  | Subsequent system - Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.3 · High |
  | Base + Threat score | - |
  | Base + Environmental score | - |
  | Base + Threat + Environmental score | - |

**Vector:** CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-55893)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-55893)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-55893)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-55893)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-55893>
* <https://github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh>
* <https://github.com/capstone-engine/capstone/pull/2968>
* <https://github.com/capstone-engine/capstone/pull/2969>