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Fencer Intel
medium 5.3

CVE-2017-7816 json

WebExtensions could use popups and panels in the extension UI to load an "about:" privileged URL, violating security checks that disallow t…

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-16791

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

WebExtensions could use popups and panels in the extension UI to load an "about:" privileged URL, violating security checks that disallow this behavior. This vulnerability affects Firefox < 56.

Patch / fix

  • Mozilla Firefox 56
  • firefox Ubuntu 14.04 LTS 56.0+build6-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 56.0+build6-0ubuntu0.16.04.1
  • firefox Ubuntu 18.04 LTS 56.0+build6-0ubuntu1

ubuntu advisories UBUNTU-CVE-2017-7816

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

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1

Exploit prediction

1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1380597 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • 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.