{"cve":"CVE-2021-21439","nvd":{"published":"2021-06-14T08:15:10.097","modified":"2026-06-17T03:35:34.680","status":"Modified","description":"DoS attack can be performed when an email contains specially designed URL in the body. It can lead to the high CPU usage and cause low quality of service, or in extreme case bring the system to a halt. This issue affects: OTRS AG ((OTRS)) Community Edition 6.0.x version 6.0.1 and later versions. OTRS AG OTRS 7.0.x version 7.0.26 and prior versions; 8.0.x version 8.0.13 and prior versions.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-755","CWE-754"],"references":["https://lists.debian.org/debian-lts-announce/2023/08/msg00040.html","https://otrs.com/release-notes/otrs-security-advisory-2021-09/","https://lists.debian.org/debian-lts-announce/2023/08/msg00040.html","https://otrs.com/release-notes/otrs-security-advisory-2021-09/"],"products":["otrs:otrs"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-21439","score":0.00877,"percentile":0.5903,"date":"2026-11-01"},"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."]}