{"cve":"CVE-2021-26918","nvd":{"published":"2021-02-09T03:15:12.850","modified":"2026-06-17T03:44:00.153","status":"Modified","description":"The ProBot bot through 2021-02-08 for Discord might allow attackers to interfere with the intended purpose of the \"Send an image when a user joins the server\" feature (or possibly have unspecified other impact) because the uploader web service allows double extensions (such as .html.jpg) with the text/html content type. NOTE: there may not be cases in which an uploader web service is customer controlled; however, the nature of the issue has substantial interaction with customer controlled configuration. NOTE: the vendor states \"This is just an uploader (like any other one) which uploads files to cloud storage and accepts various file types. There is no kind of vulnerability and it won't compromise either the client side or the server side.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-434"],"references":["http://packetstormsecurity.com/files/161347/Discord-Probot-Arbitrary-File-Upload.html","https://raw.githubusercontent.com/TheLastVvV/Vulnerability-Reports-and-CVE/main/Reports/Discord%20Probot%20-%20Unrestricted%20File%20Upload.txt","http://packetstormsecurity.com/files/161347/Discord-Probot-Arbitrary-File-Upload.html","https://raw.githubusercontent.com/TheLastVvV/Vulnerability-Reports-and-CVE/main/Reports/Discord%20Probot%20-%20Unrestricted%20File%20Upload.txt"],"products":["probot:bot"],"source":"nvd","synced_at":"2026-10-19T21:14:10.479542811+00:00"},"epss":{"cve":"CVE-2021-26918","score":0.02585,"percentile":0.85248,"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."]}