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Fencer Vulns
high 7.5

CVE-2017-5421 json

A malicious site could spoof the contents of the print preview window if popup windows are enabled, resulting in user confusion of what sit…

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-14525

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

A malicious site could spoof the contents of the print preview window if popup windows are enabled, resulting in user confusion of what site is currently loaded. This vulnerability affects Firefox < 52 and Thunderbird < 52.

Patch / fix

  • Mozilla Firefox 52
  • Mozilla Thunderbird 52
  • firefox Ubuntu 14.04 LTS 52.0+build2-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 52.0+build2-0ubuntu0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-5421

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
  • MozillaThunderbird openSUSE Tumbleweed 91.1.1-1.1
  • MozillaThunderbird Package Hub 12 52.1.0-30.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2024:10601-1openSUSE-SU-2017:1268-1

  • firefox Arch Linux 52.0-1

arch linux advisories AVG-194

Exploit prediction

1.88% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1301876 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:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns 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.