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Fencer Vulns
critical 9.8

CVE-2018-5091 json

A use-after-free vulnerability can occur during WebRTC connections when interacting with the DTMF timers.

published 2018-06-11 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-16877

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

A use-after-free vulnerability can occur during WebRTC connections when interacting with the DTMF timers. This results in a potentially exploitable crash. This vulnerability affects Firefox ESR < 52.6 and Firefox < 58.

Patch / fix

  • Mozilla Firefox ESR 52.6
  • Mozilla Firefox 58
  • firefox-esr Debian 14, Debian 13, Debian 12 52.6.0esr-1

debian advisories DEBIAN-CVE-2018-5091

  • firefox Ubuntu 14.04 LTS 58.0+build6-0ubuntu0.14.04.1
  • firefox Ubuntu 16.04 LTS 58.0+build6-0ubuntu0.16.04.1
  • firefox Ubuntu 18.04 LTS 59.0.1+build1-0ubuntu1

ubuntu advisories UBUNTU-CVE-2018-5091

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 6 52.6.0-1.el6_9
  • firefox RHEL 7 52.6.0-1.el7_4

red hat advisories RHSA-2018:0122

  • MozillaFirefox SLES for SAP 12 SP3, SLES for SAP 12 SP2, SLES for SAP 12 SP1 +10 more 52.6.0esr-109.13.1
  • MozillaFirefox SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +3 more 52.6.0esr-72.20.2

suse advisories SUSE-SU-2018:0374-1SUSE-SU-2018:0361-1

  • 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-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +14 more 52.6.0-r0

alpine advisories ALPINE-CVE-2018-5091

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-2018-5091 updated cvss 9.8

Mozilla: Use-after-free with DTMF timers (MFSA 2018-03)

  • Red Hat Enterprise Linux Client (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux Client Optional (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux Desktop (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux Desktop Optional (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox 52.6.0-1.el6_9
    +8 more products
    Red Hat Enterprise Linux Server (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux Server (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux Server Optional (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux Workstation (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 52.6.0-1.el7_4 Red Hat Enterprise Linux Workstation Optional (v. 6) firefox 52.6.0-1.el6_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 52.6.0-1.el7_4
    fixed: vendor fix RHSA-2018:0122
  • Red Hat Enterprise Linux 6 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

3.28% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

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.