CVE-2017-7783

7.5 highEPSS 14%

If a long user name is used in a username/password combination in a site URL (such as " http://UserName:Password@example.com"), the resulting modal prompt will hang in a non-responsive state or crash, causing a denial of service. This vulnerability affects Firefox < 55.

Severity

CVSS 3.0

7.5 high

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 14% chance of exploitation in the next 30 days; higher than 96% of CVEs (scores of 2026-10-31)
CWE: CWE-20
Published: 2018-06-11
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox

References

http://www.securityfocus.com/bid/100401
http://www.securitytracker.com/id/1039124
https://bugzilla.mozilla.org/show_bug.cgi?id=1360842
https://www.exploit-db.com/exploits/43020/
https://www.mozilla.org/security/advisories/mfsa2017-18/

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