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No exploitation reportedFix available

CVE-2019-9809

No exploitation reported by the sources we read.

  • Published2019-04-26
  • Fixed in66.0
  • WeaknessCWE-399

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2019-04-2617:29CVE publishedNVD

Versions per branch

NVD
Mozilla firefox
BranchAffectedFixed in
66.0< 66.066.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • firefoxUbuntu:18.04:LTSall versions · fixed in 66.0+build3-0ubuntu0.18.04.1
  • firefoxUbuntu:16.04:LTSall versions · fixed in 66.0+build3-0ubuntu0.16.04.2
  • firefoxUbuntu:14.04:LTSall versions · fixed in 66.0.1+build1-0ubuntu0.14.04.1
  • firefox-esropenSUSE:Tumbleweedall versions · fixed in 128.5.1-1.1
  • MozillaFirefoxopenSUSE:Tumbleweedall versions · fixed in 92.0-1.2
  • mozjs38Ubuntu:18.04:LTSall versions · no fixed version listedand 1 other package
  • mozjs52Ubuntu:20.04:LTSall versions · no fixed version listed

Full record on NVD

Fix

  1. Update Mozilla firefox to 66.0

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2019-04-26
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-mhpj-9q2x-79mx

Frequently asked questions

What is CVE-2019-9809?

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.

Is CVE-2019-9809 actively exploited?

Active exploitation of CVE-2019-9809 has not been confirmed. Its EPSS score was 1.6% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-9809?

CVE-2019-9809 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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Sources for this record