{"id":"CVE-2020-22552","title":"The Snap7 server component in version 1.4.1, when an attacker sends a crafted packet with COTP protocol the last-data-unit flag set to No and S7 writes a var function, the Snap7 server will be crashed.","summary":"The Snap7 server component in version 1.4.1, when an attacker sends a crafted packet with COTP protocol the last-data-unit flag set to No and S7 writes a var function, the Snap7 server will be crashed.","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"snap7_project","product":"snap7","affected":["snap7 = 1.4.1"],"published":"2020-10-28","updated":"2026-07-05","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-22552","references":[{"url":"https://sourceforge.net/p/snap7/discussion/bugfix/thread/456d76fdde/","label":"cve@mitre.org"},{"url":"https://sourceforge.net/projects/snap7/","label":"cve@mitre.org"},{"url":"http://snap7.com","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://sourceforge.net/p/snap7/discussion/bugfix/thread/456d76fdde/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://sourceforge.net/projects/snap7/","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.01473,"epssPercentile":0.7267,"ingestedAt":"2026-07-05T00:59:25.503Z","slug":"CVE-2020-22552","body":"## Overview\n\nThe Snap7 server component in version 1.4.1, when an attacker sends a crafted packet with COTP protocol the last-data-unit flag set to No and S7 writes a var function, the Snap7 server will be crashed.\n\n## Affected\n\n- `snap7 = 1.4.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":41.3,"likelihood":0.3,"exploitation":0,"ransomware":0},"changes":[]}