{"id":"CVE-2021-3831","aliases":["EUVD-2021-27078","GHSA-xq54-j4gh-pm4j"],"status":"published","title":"Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","severity":{"version":"3.0","score":7.1,"vector":"CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01841,"percentile":0.79167,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-79"],"published":"2021-12-14T10:50:10Z","modified":"2026-10-20T10:54:51Z","exploits":[{"source":"nuclei","id":"CVE-2021-3831","title":"Gnuboard 5 - Cross-Site Scripting","type":"detection template","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-3831.yaml"},{"source":"pocgithub","id":"aratane/CVE-2021-3831","title":"aratane/CVE-2021-3831","date":"2024-07-20","url":"https://github.com/aratane/CVE-2021-3831"}],"products":[{"vendor":"gnuboard","product":"gnuboard/gnuboard5"},{"vendor":"gnuboard","product":"gnuboard5"}],"references":[{"url":"https://huntr.dev/bounties/25775287-88cd-4f00-b978-692d627dff04","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Patch","Third Party Advisory","fix"]},{"url":"https://github.com/gnuboard/gnuboard5/commit/2e81619ea87bc9c0b4a073d8df3c7693a6fdbf0d","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-3831"},{"url":"https://github.com/advisories/GHSA-xq54-j4gh-pm4j"}],"sources":{"cve":[{"id":"CVE-2021-3831","title":"Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","status":"published","published":"2021-12-14T10:50:10Z","modified":"2024-08-03T17:09:09.511Z","cvss":[{"version":"3.0","score":7.1,"vector":"CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:33:04.020035Z"}],"euvd":[{"id":"EUVD-2021-27078","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","status":"published","published":"2021-12-14T10:50:10Z","modified":"2024-08-03T17:09:09Z","cvss":[{"version":"3.0","score":7.1,"vector":"CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-03T03:25:11.376657Z"}],"ghsa":[{"id":"GHSA-xq54-j4gh-pm4j","title":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross...","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","status":"published","published":"2021-12-15T00:01:27Z","modified":"2023-02-01T05:07:04Z","cwes":["CWE-79"],"updated_at":"2026-11-02T14:50:28.399252Z"}],"nvd":[{"id":"CVE-2021-3831","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","status":"published","published":"2021-12-14T11:15:07.417Z","modified":"2026-06-17T04:05:51.353Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"3.0","score":7.1,"vector":"CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:07:02.189991Z"}],"osv":[{"id":"CVE-2021-3831","description":"gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","status":"published","published":"2021-12-14T11:15:07.417Z","modified":"2026-10-20T10:54:51.527221048Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:20.843843Z"}]}}