CVE-2026-57501: CWE-266: Incorrect Privilege Assignment in zen-browser desktop
Zen is a firefox-based browser. Prior to 1.21.5b, Zen's glance and split-view context-menu actions, Open link in glance and Split link in new tab, load a page-controlled link URL with the System principal instead of the originating page's principal, allowing a malicious web page to place a link to a file URL that can load with System privileges when opened through either context-menu item and bypass the content-to-file security check that blocks an ordinary click. This issue is fixed in version 1.21.5b.
AI Analysis
Technical Summary
CVE-2026-57501 is an incorrect privilege assignment vulnerability in the Zen browser desktop (a Firefox-based browser). Before version 1.21.5b, the context-menu actions 'Open link in glance' and 'Split link in new tab' load a page-controlled link URL with the System principal rather than the originating page's principal. This behavior allows a malicious web page to craft a link to a file URL that, when opened via these context-menu items, executes with System privileges, bypassing the content-to-file security check that normally blocks such actions. The vulnerability is resolved in version 1.21.5b.
Potential Impact
The vulnerability allows a malicious web page to escalate privileges by causing links to be loaded with System-level privileges instead of the intended page-level privileges. This bypasses security checks designed to prevent unauthorized access to local file URLs, potentially enabling unauthorized access or actions on the local system. There is no indication of confidentiality, integrity, or availability impact beyond the privilege escalation described.
Mitigation Recommendations
This vulnerability is fixed in Zen browser desktop version 1.21.5b. Users and administrators should upgrade to version 1.21.5b or later to remediate this issue. No other mitigation or workaround is specified.
CVE-2026-57501: CWE-266: Incorrect Privilege Assignment in zen-browser desktop
Description
Zen is a firefox-based browser. Prior to 1.21.5b, Zen's glance and split-view context-menu actions, Open link in glance and Split link in new tab, load a page-controlled link URL with the System principal instead of the originating page's principal, allowing a malicious web page to place a link to a file URL that can load with System privileges when opened through either context-menu item and bypass the content-to-file security check that blocks an ordinary click. This issue is fixed in version 1.21.5b.
CVSS v3.1
Score 0.0none
Affected software
pkg:github/zen-browser/desktopRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-57501 is an incorrect privilege assignment vulnerability in the Zen browser desktop (a Firefox-based browser). Before version 1.21.5b, the context-menu actions 'Open link in glance' and 'Split link in new tab' load a page-controlled link URL with the System principal rather than the originating page's principal. This behavior allows a malicious web page to craft a link to a file URL that, when opened via these context-menu items, executes with System privileges, bypassing the content-to-file security check that normally blocks such actions. The vulnerability is resolved in version 1.21.5b.
Potential Impact
The vulnerability allows a malicious web page to escalate privileges by causing links to be loaded with System-level privileges instead of the intended page-level privileges. This bypasses security checks designed to prevent unauthorized access to local file URLs, potentially enabling unauthorized access or actions on the local system. There is no indication of confidentiality, integrity, or availability impact beyond the privilege escalation described.
Mitigation Recommendations
This vulnerability is fixed in Zen browser desktop version 1.21.5b. Users and administrators should upgrade to version 1.21.5b or later to remediate this issue. No other mitigation or workaround is specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-24T14:53:40.112Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a50252a68715ace43310cd5
Added to database: 07/09/2026, 22:48:10 UTC
Last enriched: 07/17/2026, 09:42:14 UTC
Last updated: 08/23/2026, 10:52:10 UTC
Views: 125
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