Discourse: Cache poisoning/XSS via color scheme cookies
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| discourse | discourse | affected |
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No data.
No data.
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| Discourse | Discourse |
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No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.590% probability within 30 days)
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| Metrics |
ssvc
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| First Time appeared |
Discourse
Discourse discourse |
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| Vendors & Products |
Discourse
Discourse discourse |
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| Description | Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, an unauthenticated attacker could send a single request with a crafted color_scheme_id (or dark_scheme_id) cookie to inject arbitrary HTML into a Discourse page. Because the cookie value was rendered into a color scheme tag without escaping, the attacker could break out of the attribute and inject a tag that bypassed Discourse's nonce-based Content Security Policy, resulting in arbitrary JavaScript execution in visitors' browsers. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0. | |
| Title | Discourse: Cache poisoning/XSS via color scheme cookies | |
| Weaknesses | CWE-79 | |
| References |
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| Metrics |
cvssV3_1
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