CVE-2026-16477

Insecure Deserialization of .cleanshot Files in CleanShot X

State: Published
Severity: 8.4 High
Published: Oct 22, 2026
Updated: Oct 22, 2026
Reserved: Jul 21, 2026

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

Scores

CVSS	Score	Vector	Source
4.0	8.4 High	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L	CERT-PL

Weaknesses

CWE-502 Deserialization of Untrusted Data

Affected Products

Product	Versions
CleanShot XMTW	4.0.0 to before 4.5.2Affected 4.6.0 to before 4.6.3Affected 4.7.0 to before 4.7.8Affected 4.8.0 to before 4.8.10Affected

References

https://cert.pl/en/posts/2026/10/CVE-2026-16477third-party-advisory
https://cleanshot.com/product

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