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Fencer Vulns
high 7.5

CVE-2016-9073 json

WebExtensions can bypass security checks to load privileged URLs and potentially escape the WebExtension sandbox.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2016-9894

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 75%
public exploits
0
none known

Summary

WebExtensions can bypass security checks to load privileged URLs and potentially escape the WebExtension sandbox. This vulnerability affects Firefox < 50.

Patch / fix

  • Mozilla Firefox 50
  • firefox Ubuntu 14.04 LTS 50.0+build2-0ubuntu0.14.04.2
  • firefox Ubuntu 16.04 LTS 50.0+build2-0ubuntu0.16.04.2

ubuntu advisories UBUNTU-CVE-2016-9073

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

  • MozillaFirefox SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +17 more 68.2.0-109.95.2

suse advisories SUSE-SU-2019:2872-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 50.1.0-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10071-1

  • firefox Arch Linux 50.0-1

arch linux advisories AVG-72

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-2016-9073 updated cvss 7.5

firefox: windows.create schema doesn't specify "format": "relativeUrl"

  • Red Hat Enterprise Linux 5 firefox, thunderbird Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, 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

1.60% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

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.