CVE-2020-35933

Newsletter <= 6.8.1 - Reflected Cross-Site Scripting

2020-08-03 00:00

Strategic Overview

Status: Patched in 6.8.2
Affected Plugin: Newsletter – Send awesome emails from WordPress
Affected Version: < 6.8.2
CVSS: 6.5Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2020-35933

View all Newsletter – Send awesome emails from WordPress vulnerabilities

At a glance

CVE-2020-35933 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Newsletter WordPress plugin, affecting versions < 6.8.2. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). The issue is fixed in version 6.8.2; sites on affected versions should update now. Disclosed August 2020, reported by Ram.

Vulnerability Overview

A Reflected Authenticated Cross-Site Scripting (XSS) vulnerability in the Newsletter plugin before 6.8.2 for WordPress allows remote attackers to trick a victim into submitting a tnpc_render AJAX request containing either JavaScript in an options parameter, or a base64-encoded JSON string containing JavaScript in the encoded_options parameter.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Newsletter < 6.8.2 takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Newsletter the fix is 6.8.2: builds < 6.8.2 are affected, anything from 6.8.2 onward is not.

Remediation

Update to version 6.8.2, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Newsletter: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Newsletter 6.8.2 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-35933 https://www.wordfence.com/threat-intel/vulnerabilities/id/95dc0d79-b65a-4bfb-89c0-569bf26232df https://nvd.nist.gov/vuln/detail/CVE-2020-35933

Related records

Same weakness class

Other vulnerabilities in Newsletter – Send awesome emails from WordPress

CVSS Vector

6.5

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityLow

This record contains material that is subject to copyright

CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

https://www.cve.org/Legal/TermsOfUse

Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.

https://www.wordfence.com/wordfence-intelligence-terms-and-conditions/