CVE-2019-9811

Exp

As part of a winning Pwn2Own entry, a researcher demonstrated a sandbox escape by installing a malicious language pack and then opening a browser feature that used the compromised translation. This vulnerability affects Firefox ESR < 60.8, Firefox < 68, and Thunderbird < 60.8.

Published: 2019-07-23 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-9811 is rated High Exploit Risk (79.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.57%). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +2.02% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2019-9811

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2019-9811

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.55% 2.57% +2.02%
2 2026-05-30 0.73% 0.55% -0.18%
3 2025-11-21 — 0.73% —

Full EPSS history (24 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-9811

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.3 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 6.0 [email protected]
5.1 2.0 MEDIUM
AV:N/AC:H/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 4.9 6.4 [email protected]

Weakness enumeration for CVE-2019-9811

OS Trackers for CVE-2019-9811

vendor priority summary link
alpine high CVE-2019-9811: 1 source package rows (firefox-esr); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2019-9811
debian not yet assigned CVE-2019-9811 not yet assigned priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11. https://security-tracker.debian.org/tracker/CVE-2019-9811
gentoo normal CVE-2019-9811: 2 GLSA(s) (201908-12, 201908-20), 4 atom(s) (mail-client/thunderbird, mail-client/thunderbird-bin, www-client/firefox, www-client/firefox-bin); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2019-9811
redhat high — https://access.redhat.com/security/cve/CVE-2019-9811
suse high CVE-2019-9811 severity important: SUSE including 243 source package names (1.0.0.1862.1.5.2:libfreebl3-3.44.1-3.16.2, 1.0.0.1862.1.5.2:libsoftokn3-3.44.1-3.16.2, …), 935 product×package rows across 121 product lines (Container bci/openjdk, Container bci/openjdk-devel, … (121 product lines)): Fixed 935. https://www.suse.com/security/cve/CVE-2019-9811/
ubuntu medium CVE-2019-9811 medium priority: Ubuntu including 5 source packages (firefox, mozjs38, mozjs52, mozjs60, thunderbird), 80 status rows across 16 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 37, released 30, ignored 13. https://ubuntu.com/security/CVE-2019-9811

Affected software / configurations for CVE-2019-9811

Vendor Product Version Raw CPE
mozilla firefox < 68.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozilla firefox_esr < 60.8 cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
mozilla thunderbird < 60.8 cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
novell suse_package_hub_for_suse_linux_enterprise 12 cpe:2.3:a:novell:suse_package_hub_for_suse_linux_enterprise:12:*:*:*:*:*:*:*
opensuse leap 15.0 cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

References for CVE-2019-9811

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00055.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00058.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00073.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00011.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00017.html Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1538007 Issue Tracking Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1539598 Exploit Issue Tracking Patch Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1563327 Exploit Issue Tracking Vendor Advisory
https://lists.debian.org/debian-lts-announce/2019/08/msg00001.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2019/08/msg00002.html Mailing List Third Party Advisory
https://security.gentoo.org/glsa/201908-12 Third Party Advisory
https://security.gentoo.org/glsa/201908-20 Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2019-21/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-22/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-23/ Vendor Advisory
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