---
id: "CVE-2026-16477"
kind: "vulnerability"
aliases: ["CVE-2026-16477"]
title: "CleanShot X for macOS: malicious project file runs code on open"
severity: "high"
cvss: 8.4
epss: 0.00287
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["cleanshot-x", "desktop-apps", "macos", "other"]
not_affected_if: ["no-untrusted-cleanshot-files", "patched-version"]
published_at: "2026-10-22T15:17:05+00:00"
first_seen_at: "2026-10-23T21:57:31+00:00"
updated_at: "2026-10-25T03:01:40+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-16477", "first_seen_at": "2026-10-23T21:57:31+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-16477", "first_seen_at": "2026-10-24T07:15:51+00:00"}]
---

# CleanShot X for macOS: malicious project file runs code on open

CleanShot X for macOS insecurely deserializes data inside a .cleanshot project file, so parsing a crafted file executes attacker-supplied code automatically. An attacker gets arbitrary code execution as the current user once the target opens the file.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run the CleanShot X version check in the app's About menu and compare against the fixed versions below.
- Look for `.cleanshot` files received from outside the team that were opened in the app.

## Fix

- Update CleanShot X to `4.5.2`, `4.6.3`, `4.7.8` or `4.8.10`, matching your major release line.
- Do not open `.cleanshot` project files from untrusted sources until updated.

## Timeline

- 2026-10-23T21:57:31+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-16477
- 2026-10-24T07:15:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-16477

## From the sources

CleanShot X for macOS insecurely deserializes untrusted data embedded in a .cleanshot project file (editable screenshot annotations). Exploitation requires an attacker to craft a malicious .cleanshot file, deliver it to the target, and have the target open it; the payload then executes automatically during parsing, resulting in arbitrary code execution in the context of the current user. Users who have never opened a .cleanshot file from an untrusted source are not affected by this vulnerability. This vulnerability was fixed in versions: 4.5.2, 4.6.3, 4.7.8 and 4.8.10

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_