CVE-2026-3471Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App
Updated under an hour ago ()
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It affects Mattermost and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Free account, 1 product
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618
- CVSS
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-939
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Mattermost
- NVD analysis
- Analyzed
- Record last updated
- May 18, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mattermost Mattermost mattermost:mattermost (from the name) | through 6.0.1; through 5.4.13; 6.2.0 not affected; 6.1.1.0 not affected; 5.13.5.0 not affected | CNA record |
mattermost mattermost_desktop mattermost:mattermost_desktop | through 5.4.13.0; from 6.0.0 through 6.0.1; from 6.1.0 before 6.2.0 | NVD |
References
- https://mattermost.com/security-updatesvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.