CVE-2019-9793

Name: CVE-2019-9793
Creator: NVD / NIST
Published: 2019-04-26T17:29:01.85+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 1.63%

Last modified Jun 17, 2026

CVE-2019-9793 is a vulnerability of currently unknown severity. A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. EPSS estimates a 1.63% chance of exploitation in the next 30 days.

Description

A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. *Note: Spectre mitigations are currently enabled for all users by default settings.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.

Metrics

EPSS Probability

1.63%

73.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 66.0
Mozilla	Firefox Esr	< 60.6
Mozilla	Thunderbird	< 60.6

References

https://access.redhat.com/errata/RHSA-2019:0966
https://access.redhat.com/errata/RHSA-2019:1144
https://bugzilla.mozilla.org/show_bug.cgi?id=1528829Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory
https://access.redhat.com/errata/RHSA-2019:0966
https://access.redhat.com/errata/RHSA-2019:1144
https://bugzilla.mozilla.org/show_bug.cgi?id=1528829Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-07/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-08/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2019-11/Vendor Advisory

Timeline

Published: Apr 26, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-9793?

How severe is CVE-2019-9793?

Severity scoring for CVE-2019-9793 is pending analysis. The EPSS model estimates a 1.63% probability of exploitation in the next 30 days.

How do I fix CVE-2019-9793?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-9793?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST