CVE-2026-42052
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBeets is the media library management system. Prior to version 2.10.0, the bundled web UI uses Underscore template interpolation mode <%= ... %> for untrusted metadata fields. In this runtime, <%= ... %> is raw insertion and HTML escaping is only performed by <%- ... %>. Rendered output is then inserted with .html(...), allowing attacker-controlled markup to become active DOM. This issue has been patched in version 2.10.0.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Beets media library management system's bundled web UI contains a DOM-based XSS vulnerability. The Underscore.js templates use raw interpolation (<%= ... %>) for untrusted metadata fields instead of the safe escaped syntax (<%- ... %>). Since rendered output is inserted with .html(), attacker-controlled HTML/JavaScript in metadata fields becomes active DOM.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- Authentication
- X
- User interaction
- P
- Scope
- X
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Beets versionRun `beets --version` or check your package manager for the installed beets package versionAffected if Version is below 2.10.0 (e.g., 2.9.x, 2.8.x, earlier)
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Verify web UI is enabledCheck if the web UI plugin or interface is configured in your beets configuration (typically in ~/.config/beets/config.yaml or /etc/beets/config.yaml) - look for the 'web' plugin or 'interface: web' settingAffected if Web UI plugin is enabled in the configuration
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Check for Underscore.js template usageInspect the beets installation directory for the bundled web UI templates (typically in the 'beets/web' directory or similar), specifically looking for template files using <%= %> raw interpolation syntax with metadata fieldsAffected if Template files contain raw interpolation (<%= %>) for untrusted metadata fields and the web UI is active
If Beets version is below 2.10.0 and the bundled web UI is enabled and in use, the environment is affected by this DOM-based XSS vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade Beets to version 2.10.0 or later, which replaces raw interpolation with escaped syntax for untrusted metadata fields.
2.10.0
- Check the currently installed beets version using: pip show beets or beets --version
- Upgrade beets to version 2.10.0 or later using: pip install --upgrade beets
- Verify the installed version: pip show beets or beets --version
- Restart the beets web UI service if it was running to load the patched version
- If using a system package manager (e.g., apt, yum, brew), update to the package providing beets version 2.10.0 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42052 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42052 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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