{"cve":"CVE-2021-22699","nvd":{"published":"2021-05-26T20:15:08.863","modified":"2026-06-17T03:37:35.310","status":"Modified","description":"Improper Input Validation vulnerability exists in Modicon M241/M251 logic controllers firmware prior to V5.1.9.1 that could cause denial of service when specific crafted requests are sent to the controller over HTTP.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-20"],"references":["https://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2021-130-05","https://download.schneider-electric.com/files?p_Doc_Ref=SEVD-2021-130-05"],"products":["schneider-electric:modicon_m241_firmware","schneider-electric:modicon_m251_firmware"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-22699","score":0.00978,"percentile":0.62182,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}