PostyBirb Plus Cross-Site Scripting (XSS) Vulnerability (CVE-2026-120190) Security Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTPostyBirb Plus versions up to and including 3.1.75
Remote attackers can inject malicious scripts via the Submission Description Editor, leading to arbitrary code execution in the user's browser context
Immediately upgrade to version 3.1.76 or later to apply the official security patch
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
It is highly recommended to upgrade the affected component to version 3.1.76 or later. Run the following commands in your project root directory to apply the update:
# For npm users
npm install postybirb-plus@3.1.76 --save
# For yarn users
yarn upgrade postybirb-plus@3.1.762. Temporary Workaround & Hardening Configuration
If an immediate upgrade is not feasible, implement a Web Application Firewall (WAF) rule or configure a reverse proxy to filter out common XSS payloads in incoming request bodies.
# Nginx configuration snippet to block potential XSS payloads in request bodies
location / {
if ($request_body ~* '(<script|javascript:|onerror=|onload=)') {
return 403 'Potential XSS Attack Blocked';
}
proxy_pass http://localhost:3000;
}3. Log Audit & IoC Verification Commands
Verify the currently installed version of PostyBirb Plus and scan application logs or database exports for potential indicators of compromise (IoCs).
# Check the installed version in package.json
grep 'postybirb-plus' package.json
# Scan application logs for common XSS injection patterns
grep -riE '(script|iframe|onerror|onload|eval\()' ./logs/ 2>/dev/null || trueScan Your Repositories for Transitive Vulnerable Dependencies in 30 Seconds
Automatically detect vulnerable packages across npm, PyPI, Maven, and Go, and open automated fix Pull Requests without breaking your build.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
A security flaw has been identified in PostyBirb Plus up to version 3.1.75. The vulnerability resides within the Submission Description Editor component, specifically in the file ui/src/views/submissions/submission-forms/form-components/DescriptionInput.tsx. Due to insufficient input validation and output sanitization of user-supplied description data, the application is susceptible to Cross-Site Scripting (CWE-79) and Code Injection (CWE-94).
2. Exploitation Mechanics & Attack Scenario
An attacker with low privileges can input malicious HTML or JavaScript payloads (such as <script> tags or inline event handlers like onerror) into the submission description field. When another user or an administrator views the affected submission form, the unsanitized payload is rendered and executed within their browser session. This can be leveraged to hijack active sessions, steal sensitive tokens, or perform unauthorized actions on behalf of the victim.
3. Infrastructure & Business Impact
Since PostyBirb Plus is utilized for managing and publishing content across multiple platforms, a successful session hijacking attack could compromise linked social media and external platform credentials. This poses a significant risk of unauthorized content distribution, brand damage, and potential lateral movement within the organization's internal network.
Official Vendor Advisories & References
A security flaw has been discovered in PostyBirb Plus up to 3.1.75. Affected by this vulnerability is an unknown functionality of the file ui/src/views/submissions/submission-forms/form-components/DescriptionInput.tsx of the component Submission Description Editor. The manipulation results in cross site scripting. The attack may be performed from remote. The exploit has been released to the public and may be used for attacks. Upgrading to version 3.1.76 addresses this issue. The patch is identified as 6b11c2345ad98ae59fd5404a9f1024eb1d10c8a4. It is advisable to upgrade the affected component.
Frequently Asked SecOps Questions (CVE-2026-120190)
FAQQ1. How critical is CVE-2026-120190 and is it actively exploited in the wild?
CVE-2026-120190 is rated CVSS 3.5 (LOW) with a 30-day EPSS exploitation probability of 0.4%. Organizations running affected versions should prioritize patching based on network exposure.
Q2. Which vendors and products are affected by CVE-2026-120190?
Primary impacted vendors include postybirb across postybirb-plus. Scope summary: PostyBirb Plus versions up to 3.1.75 (affecting DescriptionInput.tsx)
Q3. What temporary mitigations or workarounds exist for CVE-2026-120190 before patching?
[Mitigation] Immediately upgrade to version 3.1.76 or later to apply the official security patch Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2026-120190
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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