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Fencer Vulns
critical 9.8

CVE-2017-5456 json

A mechanism to bypass file system access protections in the sandbox using the file system request constructor through an IPC message.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-14560

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

A mechanism to bypass file system access protections in the sandbox using the file system request constructor through an IPC message. This allows for read and write access to the local file system. This vulnerability affects Firefox ESR < 52.1 and Firefox < 53.

Patch / fix

  • 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

ubuntu advisories UBUNTU-CVE-2017-5456

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

red hat advisories RHSA-2017:1106

  • 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

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

  • 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-2017-5456 updated cvss 9.8

Mozilla: Sandbox escape allowing local file system read access (MFSA 2017-12)

  • Red Hat Enterprise Linux 5 firefox
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) firefox 52.1.0-2.el7_3 Red Hat Enterprise Linux Client Optional (v. 7) firefox 52.1.0-2.el7_3 Red Hat Enterprise Linux Server (v. 7) firefox 52.1.0-2.el7_3 Red Hat Enterprise Linux Server Optional (v. 7) firefox 52.1.0-2.el7_3 Red Hat Enterprise Linux Workstation (v. 7) firefox 52.1.0-2.el7_3 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 5 thunderbird Red Hat Enterprise Linux 6 firefox, 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

2.73% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1344415 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Mozilla Firefox ESR
  • Mozilla Firefox

Classification

Weakness
  • CWE-732 Incorrect Permission Assignment for Critical Resource

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.