{"cve":"CVE-2021-32749","nvd":{"published":"2021-07-16T18:15:08.270","modified":"2026-06-17T03:53:33.277","status":"Modified","description":"fail2ban is a daemon to ban hosts that cause multiple authentication errors. In versions 0.9.7 and prior, 0.10.0 through 0.10.6, and 0.11.0 through 0.11.2, there is a vulnerability that leads to possible remote code execution in the mailing action mail-whois. Command `mail` from mailutils package used in mail actions like `mail-whois` can execute command if unescaped sequences (`\\n~`) are available in \"foreign\" input (for instance in whois output). To exploit the vulnerability, an attacker would need to insert malicious characters into the response sent by the whois server, either via a MITM attack or by taking over a whois server. The issue is patched in versions 0.10.7 and 0.11.3. As a workaround, one may avoid the usage of action `mail-whois` or patch the vulnerability manually.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1},"cwes":["CWE-94","CWE-78"],"references":["https://github.com/fail2ban/fail2ban/commit/2ed414ed09b3bb4c478abc9366a1ff22024a33c9","https://github.com/fail2ban/fail2ban/commit/410a6ce5c80dd981c22752da034f2529b5eee844","https://github.com/fail2ban/fail2ban/security/advisories/GHSA-m985-3f3v-cwmm","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5WHJK2X2MR2WDYZMCW7COZXJDUSDYMY6/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZRYQ77MTX5WSV33VCJLK4KBKR55QZ7ZA/"],"products":["fail2ban:fail2ban","fedoraproject:fedora"],"source":"nvd","synced_at":"2026-10-19T21:21:13.713336758+00:00"},"epss":{"cve":"CVE-2021-32749","score":0.03428,"percentile":0.88927,"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."]}