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Fencer Intel
high 7.5

CVE-2019-9809 json

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 re…

published 2019-04-26 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-19171

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

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.

Patch / fix

  • Mozilla Firefox 66
  • firefox Ubuntu 14.04 LTS 66.0.1+build1-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 66.0+build3-0ubuntu0.16.04.2
  • firefox Ubuntu 18.04 LTS 66.0+build3-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2019-9809

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1

  • firefox Arch Linux 66.0-1

arch linux advisories AVG-925

Exploit prediction

1.64% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1282430 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Mozilla Firefox

Classification

Weakness
  • CWE-399 Resource Management Errors

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.