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Fencer Intel
medium 4.3

CVE-2017-5451 json

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-14555

cvss
4.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event. The event could be used by script to affect text display to make the loaded site appear to be different from the one actually loaded within the addressbar. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Patch / fix

  • Mozilla Thunderbird 52.1
  • Mozilla Firefox ESR 52.1
  • Mozilla Firefox 53
  • firefox Ubuntu 14.04 LTS 53.0+build6-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 53.0+build6-0ubuntu0.16.04.1
  • thunderbird Ubuntu 14.04 LTS 1:52.1.1+build1-0ubuntu0.14.04.1
  • thunderbird Ubuntu 16.04 LTS 1:52.1.1+build1-0ubuntu0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-5451

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 RHEL 7 52.1.0-2.el7_3
  • thunderbird RHEL 6 52.1.0-1.el6_9
  • thunderbird RHEL 7 52.1.0-1.el7_3

red hat advisories RHSA-2017:1106RHSA-2017:1201

  • mozilla-nss SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 3.29.5-47.3.2
  • firefox-gcc5 SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 5.3.1+r233831-7.1
  • MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 52.2.0esr-72.5.2
  • firefox-libffi-gcc5 SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 5.3.1+r233831-7.1
  • MozillaFirefox-branding-SLED SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 52-24.3.44
  • MozillaFirefox-branding-SLE SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +6 more 52-31.1
  • MozillaFirefox SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +7 more 52.2.0esr-108.3

suse advisories SUSE-SU-2017:2235-1SUSE-SU-2017:1669-1

  • 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 53.0-1

arch linux advisories AVG-249

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-5451 updated cvss 4.3

Mozilla: Addressbar spoofing with onblur event (MFSA 2017-12)

  • Red Hat Enterprise Linux 5 firefox, thunderbird
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) firefox 52.1.0-2.el7_3, thunderbird 52.1.0-1.el7_3
    fixed: vendor fix RHSA-2017:1201
  • Red Hat Enterprise Linux Client Optional (v. 7) firefox 52.1.0-2.el7_3
    fixed: vendor fix RHSA-2017:1106
  • Red Hat Enterprise Linux Desktop (v. 6) thunderbird 52.1.0-1.el6_9
    fixed: vendor fix RHSA-2017:1201
  • Red Hat Enterprise Linux Server (v. 7) firefox 52.1.0-2.el7_3
    fixed: vendor fix RHSA-2017:1106
  • Red Hat Enterprise Linux Server Optional (v. 6) thunderbird 52.1.0-1.el6_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 52.1.0-2.el7_3, thunderbird 52.1.0-1.el7_3 Red Hat Enterprise Linux Workstation (v. 6) thunderbird 52.1.0-1.el6_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 52.1.0-2.el7_3, thunderbird 52.1.0-1.el7_3
    fixed: vendor fix RHSA-2017:1201
  • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 52.1.0-2.el7_3
    fixed: vendor fix RHSA-2017:1106
  • Red Hat Enterprise Linux 6 firefox
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.48% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1273537 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 4.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Affected products

  • Mozilla Thunderbird
  • Mozilla Firefox ESR
  • Mozilla Firefox

Classification

Weakness
  • CWE-20 Improper Input Validation

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.