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Fencer Vulns
critical 9.8

CVE-2023-5176 json

Memory safety bugs present in Firefox 117, Firefox ESR 115.2, and Thunderbird 115.2.

published 2023-09-27 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-57513

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

Memory safety bugs present in Firefox 117, Firefox ESR 115.2, and Thunderbird 115.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

Patch / fix

  • Mozilla Firefox 118
  • Mozilla Firefox ESR 115.3
  • Mozilla Thunderbird 115.3
  • firefox-esr Debian 12 115.3.0esr-1~deb12u1
  • firefox-esr Debian 14, Debian 13 115.3.0esr-1
  • thunderbird Debian 12 1:115.3.1-1~deb12u1
  • thunderbird Debian 14, Debian 13 1:115.3.0-1

debian advisories DEBIAN-CVE-2023-5176

  • firefox Ubuntu 20.04 LTS 118.0.1+build1-0ubuntu0.20.04.1
  • thunderbird Ubuntu 20.04 LTS 1:115.3.1+build1-0ubuntu0.20.04.1
  • thunderbird Ubuntu 22.04 LTS 1:115.3.1+build1-0ubuntu0.22.04.2

ubuntu advisories UBUNTU-CVE-2023-5176

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 8 115.3.1-1.el8_8
  • thunderbird RHEL 8 115.3.1-1.el8_8
  • thunderbird RHEL 7 115.3.1-1.el7_9
  • firefox RHEL 7 115.3.1-1.el7_9
  • thunderbird RHEL 9 115.3.1-1.el9_2
  • firefox RHEL 9 115.3.1-1.el9_2
  • firefox-x11 RHEL 9 115.3.1-1.el9_2
  • thunderbird RHEL 8.2 TUS, RHEL 8.2 E4S, RHEL 8.2 AUS 115.3.1-1.el8_2

red hat advisories RHSA-2023:5432RHSA-2023:5436RHSA-2023:5433RHSA-2023:5428RHSA-2023:5475RHSA-2023:5430

  • MozillaThunderbird SLE Workstation Extension 15 SP5, SLE Workstation Extension 15 SP4, SLE Module for Package Hub 15 SP5 +3 more 115.3.1-150200.8.133.1
  • MozillaFirefox SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 115.3.0-150200.152.108.1
  • MozillaFirefox SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 115.3.0-112.182.1
  • MozillaFirefox SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 115.3.0-150000.150.107.1

suse advisories SUSE-SU-2023:4016-1SUSE-SU-2023:3899-1SUSE-SU-2023:3898-1SUSE-SU-2023:3837-1

  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaThunderbird openSUSE Tumbleweed 115.3.0-1.1
  • MozillaFirefox openSUSE Tumbleweed 118.0.1-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:13268-1openSUSE-SU-2024:13272-1

  • firefox AlmaLinux 9 115.3.1-1.el9_2.alma.1
  • firefox-x11 AlmaLinux 9 115.3.1-1.el9_2.alma.1
  • thunderbird AlmaLinux 9 115.3.1-1.el9_2.alma

almalinux advisories ALSA-2023:5434ALSA-2023:5435

  • thunderbird Rocky Linux 9 115.3.1-1.el9_2
  • thunderbird Rocky Linux 8 115.3.1-1.el8_8

rocky linux advisories RLSA-2023:5435RLSA-2023:5428

  • firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +3 more 115.3.0-r0

alpine advisories ALPINE-CVE-2023-5176

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

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-2023-5176 updated cvss 9.8

Mozilla: Memory safety bugs fixed in Firefox 118, Firefox ESR 115.3, and Thunderbird 115.3

  • Red Hat Enterprise Linux 6 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 115.3.1-1.el8_8, thunderbird 115.3.1-1.el8_8
    fixed: vendor fix RHSA-2023:5433
  • Red Hat Enterprise Linux AppStream (v. 9) firefox 115.3.1-1.el9_2, firefox-x11 115.3.1-1.el9_2, thunderbird 115.3.1-1.el9_2
    fixed: vendor fix RHSA-2023:5434
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 115.3.1-1.el8_2, thunderbird 115.3.1-1.el8_2
    fixed: vendor fix RHSA-2023:5426
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 115.3.1-1.el8_4, thunderbird 115.3.1-1.el8_4
    fixed: vendor fix RHSA-2023:5437
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) firefox 115.3.1-1.el8_1, thunderbird 115.3.1-1.el8_1
    fixed: vendor fix RHSA-2023:5440
  • Red Hat Enterprise Linux AppStream E4S (v. 8.2) firefox 115.3.1-1.el8_2, thunderbird 115.3.1-1.el8_2
    fixed: vendor fix RHSA-2023:5426
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) firefox 115.3.1-1.el8_4, thunderbird 115.3.1-1.el8_4
    fixed: vendor fix RHSA-2023:5437
show 5 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) firefox 115.3.1-1.el8_6, thunderbird 115.3.1-1.el8_6
    fixed: vendor fix RHSA-2023:5436
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) firefox 115.3.1-1.el9_0, thunderbird 115.3.1-1.el9_0
    fixed: vendor fix RHSA-2023:5427
  • Red Hat Enterprise Linux AppStream TUS (v. 8.2) firefox 115.3.1-1.el8_2, thunderbird 115.3.1-1.el8_2
    fixed: vendor fix RHSA-2023:5426
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) firefox 115.3.1-1.el8_4, thunderbird 115.3.1-1.el8_4
    fixed: vendor fix RHSA-2023:5437
  • Red Hat Enterprise Linux Client (v. 7) firefox 115.3.1-1.el7_9, thunderbird 115.3.1-1.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) firefox 115.3.1-1.el7_9 Red Hat Enterprise Linux Server (v. 7) firefox 115.3.1-1.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 115.3.1-1.el7_9, thunderbird 115.3.1-1.el7_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 115.3.1-1.el7_9, thunderbird 115.3.1-1.el7_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 115.3.1-1.el7_9
    fixed: vendor fix RHSA-2023:5477

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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
18 mo ago

Exploit prediction

1.39% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Mozilla Firefox
  • Mozilla Firefox ESR
  • Mozilla Thunderbird

Classification

Weakness

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.