CVE-2026-16477: CWE-502: Deserialization of Untrusted Data in MTW 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
CVSS v4.0
Score 8.4high
Affected software
MTW
CleanShot X
pkg:github/mtw/CleanShotXRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-16477 is a deserialization of untrusted data vulnerability (CWE-502) in CleanShot X for macOS. The vulnerability arises from insecure deserialization of data embedded in .cleanshot project files used for editable screenshot annotations. Exploitation requires an attacker to deliver a crafted malicious .cleanshot file to the target, which upon opening, executes arbitrary code in the context of the current user. The vulnerability affects multiple version ranges prior to the patched releases 4.5.2, 4.6.3, 4.7.8, and 4.8.10.
Potential Impact
Successful exploitation results in arbitrary code execution with the privileges of the current user. This can lead to compromise of the user's environment, data theft, or further system compromise. However, exploitation requires user interaction by opening a malicious .cleanshot file from an untrusted source. Users who do not open such files are not affected.
Mitigation Recommendations
This vulnerability has been fixed in CleanShot X versions 4.5.2, 4.6.3, 4.7.8, and 4.8.10. Users should upgrade to one of these versions or later to remediate the issue. Until patched, users should avoid opening .cleanshot files from untrusted or unknown sources to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CERT-PL
- Date Reserved
- 2026-07-21T14:22:56.242Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ada25314d27ba8daa5f901f
Added to database: 10/22/2026, 15:01:05 UTC
Last enriched: 10/22/2026, 15:15:23 UTC
Last updated: 10/22/2026, 19:31:41 UTC
Views: 9
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