CVE Vulnerabilities

CVE-2021-43862

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Published: Dec 30, 2021 | Modified: Nov 21, 2024
CVSS 3.x
5.4
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS 2.x
2.1 LOW
AV:N/AC:H/Au:S/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

jQuery Terminal Emulator is a plugin for creating command line interpreters in your applications. Versions prior to 2.31.1 contain a low impact and limited cross-site scripting (XSS) vulnerability. The code for XSS payload is always visible, but an attacker can use other techniques to hide the code the victim sees. If the application uses the execHash option and executes code from URL, the attacker can use this URL to execute their code. The scope is limited because the javascript attribute used is added to span tag, so no automatic execution like with onerror on images is possible. This issue is fixed in version 2.31.1. As a workaround, the user can use formatting that wrap whole user input and its no op. The code for this workaround is available in the GitHub Security Advisory. The fix will only work when user of the library is not using different formatters (e.g. to highlight code in different way).

Weakness

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as “<”, “>”, and “&” that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.

Affected Software

Name Vendor Start Version End Version
Jquery.terminal Jquery.terminal_project * 2.31.1 (excluding)

Potential Mitigations

  • Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
  • The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.

References