What’s Vulnerable › Vulnerabilities
CVE-2023-2808: Lack of URL normalization allows rendering previews for disallowed domains
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2023-05-29 · updated 2026-06-17
- Weakness: CWE-20
Description
Mattermost fails to normalize UTF confusable characters when determining if a preview should be generated for a hyperlink, allowing an attacker to trigger link preview on a disallowed domain using a specially crafted link.
Affected products
- Mattermost App Framework: from 5.34.0 before 7.1.9; from 7.2.0 before 7.8.4; from 7.9.0 before 7.9.3 — fixed in 7.1.9, 7.8.4, 7.9.3
How to fix
Upgrade to a fixed version: Mattermost App Framework 7.1.9, 7.8.4, 7.9.3. Check the vendor advisory for mitigations.
References
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