CVE-2018-18500: canonical ubuntu_linux Use After Free
Vulnerability summary
CVE-2018-18500 is a critical (CVSS 9.8) Use After Free vulnerability in canonical ubuntu_linux. EPSS estimates a 12.66% chance of exploitation in the next 30 days, higher than 96.2% of scored vulnerabilities.
Severe, CVSS 9.8 (NVD); no exploitation reported by the 5 checked sources; EPSS 13% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 21 · Related 11Timeline
- 05-02-2019PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
Description
A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements. This results in the stream parser object being freed while still in use, leading to a potentially exploitable crash. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · AlpineEcosystem advisory · calculated9.8CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
12.66%
Chance of exploitation in the next 30 days
Percentile
96%
Versus all other CVEs
30-day change
No change 0.00 pp
From 12.66% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat6 products
- enterprise_linux_desktop6.0 | 7.0
- enterprise_linux_server6.0 | 7.0
- enterprise_linux_server_aus7.6
- enterprise_linux_server_eus7.6
- enterprise_linux_server_tus7.6
Ubuntu4 products
- firefox< 65.0+build2-0ubuntu0.14.04.1 | < 65.0+build2-0ubuntu0.16.04.1 | < 65.0+build2-0ubuntu0.18.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- thunderbird< 1:60.5.1+build2-0ubuntu0.14.04.1 | < 1:60.5.1+build2-0ubuntu0.16.04.1 | < 1:60.5.1+build2-0ubuntu0.18.04.1
Debian3 products
- firefox-esr< 60.5.0esr-1
- thunderbird< 1:60.5.0-1
- debian_linuxEOL8.0 | 9.0
Mozilla3 products
- firefox< 65.0
- firefox esr< 60.5
- thunderbird< 60.5
Alpine1 product
- firefox-esr< 60.5.0-r0
Canonical1 product
- ubuntu_linuxEOL14.04 | 16.04 | 18.04 | 18.10
6 vendors · 18 products
References
25 linksShow all 25 references
lists.debian.org/debian-lts-announce/2019/02/msg00024.htmlMailing ListX Refsource MLISTThird Party Advisory- lists.debian.org/debian-lts-announce/2019/01/msg00025.htmlMailing ListX Refsource MLISTThird Party Advisory