CVE-2019-9809

critical

Published — · Modified —

CVSS v3

—

CVSS v2

—

VIR risk

9.5

Description

If the source for resources on a page is through an FTP connection, it is possible to trigger a series of modal alert messages for these resources through invalid credentials or locations. These messages cannot be immediately dismissed, allowing for a denial of service (DOS) attack. This vulnerability affects Firefox < 66.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2019-9809

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-201903-11

OS impact

OS	Version	Status	Fixed in
arch		fixed	`66.0-1`
debian	sid	fixed	`66.0-1`

References

https://security.archlinux.org/ASA-201903-11
https://security-tracker.debian.org/tracker/CVE-2019-9809

Verify integrity in audit chain (admin only). AS-IS.