8.4
HIGH CVSS 4.0
CVE-2026-16477
Insecure Deserialization of .cleanshot Files in CleanShot X
Description

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

INFO

Published Date :

Oct. 22, 2026, 3:17 p.m.

Last Modified :

Oct. 22, 2026, 5:21 p.m.

Remotely Exploit :

No
Affected Products

The following products are affected by CVE-2026-16477 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Mtw cleanshot_x
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH 4bb8329e-dd38-46c1-aafb-9bf32bcb93c6
CVSS 4.0 HIGH [email protected]
Solution
Update CleanShot X to a patched version to prevent arbitrary code execution.
  • Update CleanShot X to version 4.5.2 or later.
  • Avoid opening untrusted .cleanshot files.
  • Ensure the application is updated to the latest version.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-16477.

URL Resource
https://cert.pl/en/posts/2026/10/CVE-2026-16477
https://cleanshot.com/
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-16477 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-16477 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-16477 vulnerability anywhere in the article.

  • cert.pl
Vulnerability in MTW CleanShot X software

Vulnerability in MTW CleanShot X software CVE ID CVE-2026-16477 Publication date 22 October 2026 Vendor MTW Product CleanShot X Vulnerable versions From 4.0.0 to 4.5.2 Vulnerability type (CWE) Deseria ... Read more

Published Date: Oct 22, 2026 (4 hours, 13 minutes ago)

The following table lists the changes that have been made to the CVE-2026-16477 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Oct. 22, 2026

    Action Type Old Value New Value
    Added Description 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
    Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-502
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/16xxx/CVE-2026-16477.json">CVE-2026-16477</a>
    Added Reference https://cert.pl/en/posts/2026/10/CVE-2026-16477
    Added Reference https://cleanshot.com/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.