{"cve":"CVE-2021-43083","nvd":{"published":"2021-12-19T09:15:06.633","modified":"2026-06-17T04:10:29.583","status":"Modified","description":"Apache PLC4X - PLC4C (Only the C language implementation was effected) was vulnerable to an unsigned integer underflow flaw inside the tcp transport. Users should update to 0.9.1, which addresses this issue. However, in order to exploit this vulnerability, a user would have to actively connect to a mallicious device which could send a response with invalid content. Currently we consider the probability of this being exploited as quite minimal, however this could change in the future, especially with the industrial networks growing more and more together.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-191","CWE-119"],"references":["http://www.openwall.com/lists/oss-security/2021/12/20/2","https://lists.apache.org/thread/jxx6qc84z60xbbhn6vp2s5qf09psrtc7","http://www.openwall.com/lists/oss-security/2021/12/20/2","https://lists.apache.org/thread/jxx6qc84z60xbbhn6vp2s5qf09psrtc7"],"products":["apache:plc4x"],"source":"nvd","synced_at":"2026-10-19T21:25:41.256909649+00:00"},"epss":{"cve":"CVE-2021-43083","score":0.01985,"percentile":0.80588,"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."]}