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Fencer Intel
critical 9.8

CVE-2017-7800 json

A use-after-free vulnerability can occur in WebSockets when the object holding the connection is freed before the disconnection operation i…

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2017-16775

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

A use-after-free vulnerability can occur in WebSockets when the object holding the connection is freed before the disconnection operation is finished. This results in an exploitable crash. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

Patch / fix

  • Mozilla Thunderbird 52.3
  • Mozilla Firefox ESR 52.3
  • Mozilla Firefox 55
  • firefox-esr Debian 14, Debian 13, Debian 12 52.3.0esr-1

debian advisories DEBIAN-CVE-2017-7800

  • firefox Ubuntu 14.04 LTS 55.0.1+build2-0ubuntu0.14.04.2
  • firefox Ubuntu 16.04 LTS 55.0.1+build2-0ubuntu0.16.04.2
  • thunderbird Ubuntu 14.04 LTS 1:52.3.0+build1-0ubuntu0.14.04.1
  • thunderbird Ubuntu 16.04 LTS 1:52.3.0+build1-0ubuntu0.16.04.1
  • thunderbird Ubuntu 18.04 LTS 1:52.4.0+build1-0ubuntu2

ubuntu advisories UBUNTU-CVE-2017-7800

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

  • thunderbird RHEL 6 52.3.0-1.el6_9
  • thunderbird RHEL 7 52.3.0-1.el7_4
  • firefox RHEL 6 52.3.0-3.el6_9
  • firefox RHEL 7 52.3.0-2.el7_4

red hat advisories RHSA-2017:2534RHSA-2017:2456

  • MozillaFirefox SLES for SAP 12 SP3, SLES for SAP 12 SP2, SLES for SAP 12 SP1 +10 more 52.3.0esr-109.3.1
  • MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 52.3.0esr-72.9.1
  • MozillaFirefox-branding-SLED SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +2 more 52-24.5.1

suse advisories SUSE-SU-2017:2589-1SUSE-SU-2017:2302-1

  • 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 52.3.0-42.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:10600-1openSUSE-SU-2024:10601-1openSUSE-SU-2017:2209-1

  • firefox Arch Linux 55.0-1
  • thunderbird Arch Linux 52.3.0-1

arch linux advisories AVG-375AVG-385

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-2017-7800 updated cvss 9.8

Mozilla: Use-after-free in WebSockets during disconnection (MFSA 2017-19)

  • Red Hat Enterprise Linux Client (v. 7) firefox 52.3.0-2.el7_4, thunderbird 52.3.0-1.el7_4 Red Hat Enterprise Linux Client Optional (v. 7) firefox 52.3.0-2.el7_4 Red Hat Enterprise Linux Desktop (v. 6) firefox 52.3.0-3.el6_9, thunderbird 52.3.0-1.el6_9 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 52.3.0-3.el6_9 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 52.3.0-3.el6_9 Red Hat Enterprise Linux Server (v. 6) firefox 52.3.0-3.el6_9
    +7 more products
    Red Hat Enterprise Linux Server (v. 7) firefox 52.3.0-2.el7_4 Red Hat Enterprise Linux Server Optional (v. 6) firefox 52.3.0-3.el6_9, thunderbird 52.3.0-1.el6_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 52.3.0-2.el7_4, thunderbird 52.3.0-1.el7_4 Red Hat Enterprise Linux Workstation (v. 6) firefox 52.3.0-3.el6_9, thunderbird 52.3.0-1.el6_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 52.3.0-2.el7_4, thunderbird 52.3.0-1.el7_4 Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 52.3.0-3.el6_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 52.3.0-2.el7_4
    fixed: vendor fix RHSA-2017:2456

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

2.94% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1374047 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 Thunderbird
  • Mozilla Firefox ESR
  • Mozilla Firefox

Classification

Weakness

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.