CVE-2021-25074

WebP Converter for Media <= 4.0.2 - Unauthenticated Open Redirect

2021-12-27 00:00

Strategic Overview

Status: Patched in 4.0.3
Affected Plugin: Converter for Media – Optimize images | Convert WebP & AVIF
Affected Version: < 4.0.3
CVSS: 6.1Medium
Weakness type: CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')
CVE: CVE-2021-25074

View all Converter for Media – Optimize images | Convert WebP & AVIF vulnerabilities

At a glance

CVE-2021-25074 is a medium-severity URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the Converter for Media WordPress plugin, affecting versions < 4.0.3. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.0.3; sites on affected versions should update now. Disclosed December 2021, reported by Krzysztof Zając.

Vulnerability Overview

The WebP Converter for Media WordPress plugin before 4.0.3 contains a file (passthru.php) which does not validate the src parameter before redirecting the user to it, leading to an Open Redirect issue

Technical Analysis

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

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

Reaching this weakness in Converter for Media < 4.0.3 takes no account at all. An open redirect is a page that takes a destination from the request and sends the browser there without checking that the destination belongs to the site.

A link that starts on a trusted domain finishes on an attacker's, which is what makes phishing and consent-screen abuse credible to the person clicking it. For Converter for Media the fix is 4.0.3: builds < 4.0.3 are affected, anything from 4.0.3 onward is not.

Remediation

Update to version 4.0.3, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Converter for Media 4.0.3 closes this, and updating the plugin is the step that ends it.

Firewall
Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-25074 https://www.wordfence.com/threat-intel/vulnerabilities/id/16919724-e495-492e-8cc7-639e6d8473c2 https://nvd.nist.gov/vuln/detail/CVE-2021-25074

Related records

Other vulnerabilities in Converter for Media – Optimize images | Convert WebP & AVIF

CVSS Vector

6.1

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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