{"id":"CVE-2026-16477","kind":"vulnerability","aliases":["CVE-2026-16477"],"related":[],"title":"CleanShot X for macOS: malicious project file runs code on open","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","summary":"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.","severity":"high","cvss":8.4,"epss":0.00287,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cleanshot-x","desktop-apps","macos","other"],"not_affected_if":["no-untrusted-cleanshot-files","patched-version"],"how_to_check":"- Run the CleanShot X version check in the app's About menu and compare against the fixed versions below.\n- 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.\n- Do not open `.cleanshot` project files from untrusted sources until updated.","status":"open","published_at":"2026-10-22T15:17:05+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","triaged_at":"2026-10-25T03:01:40+00:00","updated_at":"2026-10-25T03:01:40+00:00","category":"other","confidence":0.8,"triage":{"at":"2026-10-25T03:01:40Z","model":"claude-haiku-5-5","output":{"fix":"- Update CleanShot X to `4.5.2`, `4.6.3`, `4.7.8` or `4.8.10`, matching your major release line.\n- Do not open `.cleanshot` project files from untrusted sources until updated.","reach":"local","title":"CleanShot X for macOS: malicious project file runs code on open","impact":"high","summary":"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.","category":"other","nicknames":[],"who_cares":["macos","desktop-apps","cleanshot-x"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker runs code as the current user after the file is opened.","analyst_note":"","how_to_check":"- Run the CleanShot X version check in the app's About menu and compare against the fixed versions below.\n- Look for `.cleanshot` files received from outside the team that were opened in the app.","needs_analyst":false,"not_affected_if":["no-untrusted-cleanshot-files","patched-version"],"who_is_affected":"Users of CleanShot X on macOS who open .cleanshot project files that came from untrusted sources are exposed, since the payload runs when the file is parsed. Users who have never opened such a file from an untrusted source are not affected, and the sources do not describe a server-side or network trigger.","user_interaction":"yes","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000615,"input_tokens":3457,"output_tokens":539,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-16477':14A,17A '-2026':13A,16A '4.5.2':145C '4.6.3':146C '4.7.8':147C '4.8.10':149C 'affect':135C 'annot':80C 'app':23B 'arbitrari':51B,111C 'attack':44B,49B,84C 'attacker-suppli':43B 'automat':47B,106C 'cleanshot':1A,19B,25B,34B,64C,75C,89C,127C 'cleanshot-x':18B 'code':9A,46B,52B,112C 'context':116C 'craft':40B,86C 'current':56B,119C 'cve':12A,15A 'data':31B,71C 'deliv':91C 'deseri':30B,69C 'desktop':22B 'desktop-app':21B 'edit':78C 'embed':72C 'execut':42B,53B,105C,113C 'exploit':81C 'file':7A,36B,41B,63B,77C,90C,128C 'fix':142C 'get':50B 'insecur':29B,68C 'insid':32B 'maco':4A,24B,28B,67C 'malici':5A,88C 'never':124C 'open':11A,61B,100C,125C 'pars':38B,108C 'payload':103C 'project':6A,35B,76C 'requir':82C 'result':109C 'run':8A 'screenshot':79C 'sourc':132C 'suppli':45B 'target':60B,95C,99C 'untrust':70C,131C 'user':57B,120C,121C 'version':144C 'vulner':138C,140C 'x':2A,20B,26B,65C","nicknames":[],"mitigations":[],"who_affected":"Users of CleanShot X on macOS who open .cleanshot project files that came from untrusted sources are exposed, since the payload runs when the file is parsed. Users who have never opened such a file from an untrusted source are not affected, and the sources do not describe a server-side or network trigger.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T15:17:05+00:00","kev":null,"cvss_vector":"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/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","cvss_by":"cvd@cert.pl","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-16477","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16477","severity":null,"published_at":"2026-10-22T15:17:05+00:00","modified_at":"2026-10-22T19:17:50+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-16477","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-16477","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:51+00:00","fetched_at":"2026-10-24T07:15:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}