CVE-2026-42052: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in beetbox beets
Beets 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.
AI Analysis
Technical Summary
The vulnerability in beets before version 2.10.0 involves improper neutralization of input during web page generation (CWE-79). The bundled web UI used Underscore.js template interpolation mode <%= ... %> for untrusted metadata fields, which inserts raw HTML without escaping. Since the rendered output is inserted using .html(...), this allows attacker-controlled markup to execute in the DOM, leading to cross-site scripting. The issue is resolved in beets version 2.10.0.
Potential Impact
An attacker can inject malicious scripts via untrusted metadata fields in the beets web UI, potentially leading to cross-site scripting attacks. This can result in execution of arbitrary scripts in the context of the victim's browser, which may lead to session hijacking, data theft, or other client-side impacts. The CVSS 4.0 score is 6.0 (medium severity), reflecting network attack vector, low attack complexity, and partial user interaction required.
Mitigation Recommendations
Upgrade beets to version 2.10.0 or later, where this vulnerability has been patched. No other specific mitigations are indicated. Patch status is confirmed by the vendor stating the issue is fixed in 2.10.0.
CVE-2026-42052: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in beetbox beets
Description
Beets 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.
CVSS v4.0
Score 6.0medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in beets before version 2.10.0 involves improper neutralization of input during web page generation (CWE-79). The bundled web UI used Underscore.js template interpolation mode <%= ... %> for untrusted metadata fields, which inserts raw HTML without escaping. Since the rendered output is inserted using .html(...), this allows attacker-controlled markup to execute in the DOM, leading to cross-site scripting. The issue is resolved in beets version 2.10.0.
Potential Impact
An attacker can inject malicious scripts via untrusted metadata fields in the beets web UI, potentially leading to cross-site scripting attacks. This can result in execution of arbitrary scripts in the context of the victim's browser, which may lead to session hijacking, data theft, or other client-side impacts. The CVSS 4.0 score is 6.0 (medium severity), reflecting network attack vector, low attack complexity, and partial user interaction required.
Mitigation Recommendations
Upgrade beets to version 2.10.0 or later, where this vulnerability has been patched. No other specific mitigations are indicated. Patch status is confirmed by the vendor stating the issue is fixed in 2.10.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-23T16:05:01.710Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69f8dc9fcbff5d86103c00f6
Added to database: 05/04/2026, 17:51:27 UTC
Last enriched: 06/24/2026, 14:23:25 UTC
Last updated: 08/02/2026, 07:17:57 UTC
Views: 84
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