CVE-2021-26918

CRITICAL

Bot < 2021-02-08 - Unrestricted File Upload

Title source: rule
STIX 2.1

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.

Scores

CVSS v3 9.8
EPSS 0.0078
EPSS Percentile 73.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-434
Status published
Products (1)
probot/bot < 2021-02-08
Published Feb 09, 2021
Tracked Since Feb 18, 2026