What’s Vulnerable › Vulnerabilities

CVE-2018-5091

• Severity: critical (CVSS 9.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-06-11 · updated 2026-06-17
• Weakness: CWE-416

Description

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.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 17.10
• Debian Linux: 7.0, 8.0, 9.0
• Mozilla Firefox: before 58.0; before 52.6.0 — fixed in 52.6.0, 58.0
• Red Hat Enterprise Linux: 6.0, 7.0
• RedHat Enterprise Linux Desktop: 6.0, 7.0
• RedHat Enterprise Linux Server: 6.0, 7.0
• RedHat Enterprise Linux Server Aus: 7.3, 7.4
• RedHat Enterprise Linux Server Eus: 7.3, 7.4, 7.5
• RedHat Enterprise Linux Workstation: 6.0, 7.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 52.6.0, 58.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/102783
• http://www.securitytracker.com/id/1040270
• https://access.redhat.com/errata/RHSA-2018:0122
• https://bugzilla.mozilla.org/show_bug.cgi?id=1423086
• https://lists.debian.org/debian-lts-announce/2018/01/msg00030.html
• https://usn.ubuntu.com/3544-1/
• https://www.debian.org/security/2018/dsa-4096
• https://www.debian.org/security/2018/dsa-4102
• https://www.mozilla.org/security/advisories/mfsa2018-02/
• https://www.mozilla.org/security/advisories/mfsa2018-03/
• http://www.securityfocus.com/bid/102783
• http://www.securitytracker.com/id/1040270

Get alerted when CVE-2018-5091 or the next vulnerability affects your stack