phoenix_html allows Cross-site Scripting in HEEx class attributes

MEDIUM 6.1CVE-2021-46871 · GHSA-5g2h-9x5v-5h3x · GHSA-j3gg-r6gp-95q2 · Published 10/01/2023 · updated 17/06/2026

In short

CVE-2021-46871 is a MEDIUM (CVSS 6.1) vulnerability affecting phoenix_html, phoenix html (phoenixframework), phoenix_html.
Chance of exploitation in the next 30 days (EPSS): 0.43%, higher than 37.8% of all vulnerabilities.
Fix: update to 3.0.4 or later.

Package	Affected versions	Patched versions
phoenix_html Hex	`< 3.0.4`	`3.0.4`
phoenix html phoenixframework	`< 3.0.4`	`3.0.4`
phoenix_html npm	`< 3.0.4`	`3.0.4`

tag.ex in Phoenix Phoenix.HTML (aka phoenix_html) before 3.0.4 allows XSS in HEEx class attributes

NVD description

tag.ex in Phoenix Phoenix.HTML (aka phoenix_html) before 3.0.4 allows XSS in HEEx class attributes.

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