What’s Vulnerable › Vulnerabilities

CVE-2022-21650: Stored XSS via html file upload in convos

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-01-04 · updated 2026-06-17
• Weakness: CWE-79

Description

Convos is an open source multi-user chat that runs in a web browser. You can't use SVG extension in Convos' chat window, but you can upload a file with an .html extension. By uploading an SVG file with an html extension the upload filter can be bypassed. This causes Stored XSS. Also, after uploading a file the XSS attack is triggered upon a user viewing the file. Through this vulnerability, an attacker is capable to execute malicious scripts. Users are advised to update as soon as possible.

Affected products

• convos-chat convos: from 6.48 before 6.52 — fixed in 6.52

How to fix

Upgrade to a fixed version: convos-chat convos 6.52. Check the vendor advisory for mitigations.

References

• https://blog.pocas.kr/2021/12/30/2021-12-30-s-xss-convos-chat/#First-vulnerability
• https://github.com/convos-chat/convos/commit/5c0a1ec9a2c147bc3b63fd5a48da5f32e18fe5df
• https://github.com/convos-chat/convos/security/advisories/GHSA-mm2v-4v7g-m695
• https://www.huntr.dev/bounties/ae424798-de01-4972-b73b-2db674f82368/
• https://blog.pocas.kr/2021/12/30/2021-12-30-s-xss-convos-chat/#First-vulnerability
• https://github.com/convos-chat/convos/commit/5c0a1ec9a2c147bc3b63fd5a48da5f32e18fe5df
• https://github.com/convos-chat/convos/security/advisories/GHSA-mm2v-4v7g-m695
• https://www.huntr.dev/bounties/ae424798-de01-4972-b73b-2db674f82368/

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