CVE-2019-9788: mozilla firefox Out-of-bounds Write
Vulnerability summary
CVE-2019-9788 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in mozilla firefox. EPSS estimates a 2.24% chance of exploitation in the next 30 days, higher than 82.8% of scored vulnerabilities.
Severe, CVSS 9.8 (NVD); no exploitation reported by the 5 checked sources; EPSS 2% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 23 · Related 11Timeline
- 26-04-2019PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Mozilla developers and community members reported memory safety bugs present in Firefox 65, Firefox ESR 60.5, and Thunderbird 60.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.
CVSS metrics
6 scores · 4 sources · 3 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · AlpineEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
2.24%
Chance of exploitation in the next 30 days
Percentile
83%
Versus all other CVEs
30-day change
No change 0.00 pp
From 2.24% 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.
Redhat4 products
- enterprise_linux8.0
- enterprise_linux_eus8.1 | 8.2 | 8.4
- enterprise_linux_server_aus8.2 | 8.4
- enterprise_linux_server_tus8.2 | 8.4
Ubuntu4 products
- firefox< 66.0.1+build1-0ubuntu0.14.04.1 | < 66.0+build3-0ubuntu0.16.04.2 | < 66.0+build3-0ubuntu0.18.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- thunderbird< 1:60.6.1+build2-0ubuntu0.14.04.1 | < 1:60.6.1+build2-0ubuntu0.16.04.1 | < 1:60.6.1+build2-0ubuntu0.18.04.1
Mozilla3 products
- firefox≥ unspecified, < 66 | < 60.6.0 | < 66.0
- firefox esr≥ unspecified, < 60.6
- thunderbird≥ unspecified, < 60.6 | < 60.6.0
Debian2 products
- firefox-esr< 60.6.0esr-1
- thunderbird< 1:60.6.1-1
Alpine1 product
- firefox-esr< 60.6.1-r0
5 vendors · 14 products
