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Fencer Intel
high 7.3

CVE-2017-5386 json

WebExtension scripts can use the "data:" protocol to affect pages loaded by other web extensions using this protocol, leading to potential…

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-14490

cvss
7.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

WebExtension scripts can use the "data:" protocol to affect pages loaded by other web extensions using this protocol, leading to potential data disclosure or privilege escalation in affected extensions. This vulnerability affects Firefox ESR < 45.7 and Firefox < 51.

Patch / fix

  • Mozilla Firefox ESR 45.7
  • Mozilla Firefox 51
  • firefox-esr Debian 14, Debian 13, Debian 12 45.7.0esr-1

debian advisories DEBIAN-CVE-2017-5386

  • firefox Ubuntu 14.04 LTS 51.0.1+build2-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 51.0.1+build2-0ubuntu0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-5386

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 5 45.7.0-2.el5_11
  • firefox RHEL 6 45.7.0-2.el6_8
  • firefox RHEL 7 45.7.0-2.el7_3

red hat advisories RHSA-2017:0190

  • MozillaFirefox SLES for SAP 12 SP2, SLES for SAP 12 SP1, SLES for SAP 12 +8 more 45.7.0esr-99.1
  • MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +6 more 45.7.0esr-65.2

suse advisories SUSE-SU-2017:0427-1SUSE-SU-2017:0426-1

  • 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-esr Alpine 3.5 45.7.0-r0

alpine advisories ALPINE-CVE-2017-5386

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox Arch Linux 51.0.1-1

arch linux advisories AVG-157

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-2017-5386 updated cvss 7.3

Mozilla: WebExtensions can use data: protocol to affect other extensions (MFSA 2017-02)

  • Red Hat Enterprise Linux (v. 5 server) firefox 45.7.0-2.el5_11 Red Hat Enterprise Linux Client (v. 7) firefox 45.7.0-2.el7_3 Red Hat Enterprise Linux Client Optional (v. 7) firefox 45.7.0-2.el7_3 Red Hat Enterprise Linux Desktop (v. 5 client) firefox 45.7.0-2.el5_11 Red Hat Enterprise Linux Desktop (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 45.7.0-2.el6_8
    +9 more products
    Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Server (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Server (v. 7) firefox 45.7.0-2.el7_3 Red Hat Enterprise Linux Server Optional (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Server Optional (v. 7) firefox 45.7.0-2.el7_3 Red Hat Enterprise Linux Workstation (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Workstation (v. 7) firefox 45.7.0-2.el7_3 Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 45.7.0-2.el6_8 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 45.7.0-2.el7_3
    fixed: vendor fix RHSA-2017:0190
  • Red Hat Enterprise Linux 5 thunderbird Red Hat Enterprise Linux 6 thunderbird Red Hat Enterprise Linux 7 thunderbird
    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

2.22% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1319070 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 7.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Firefox ESR
  • Mozilla Firefox

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.