CVE-2026-3471Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App
- 6.5MediumCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 92% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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
Timeline
ID reserved
By Mattermost
- 3 months later
· 3 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| MattermostCNA (assigner) | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.18% · top 92% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
- affected ≤ 6.0.1
- affected ≤ 5.4.13
- unaffected 6.2.0
- unaffected 6.1.1.0
- unaffected 5.13.5.0
What to do
Solution: Update Mattermost Desktop App to versions 6.2.0, 6.1.1.0, 5.13.5.0 or higher.
References
References1
- MMSA-2026-00618 (opens in a new tab)vendor-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-30757 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-3471)Record last updated .