CVE-2023-4056

Name: CVE-2023-4056
Creator: NVD / NIST
Published: 2023-08-01T16:15:10.02+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.85%

Last modified Jun 17, 2026

CVE-2023-4056 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Memory safety bugs present in Firefox 115, Firefox ESR 115.0, Firefox ESR 102.13, Thunderbird 115.0, and Thunderbird 102.13. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. EPSS estimates a 0.85% chance of exploitation in the next 30 days.

Description

Memory safety bugs present in Firefox 115, Firefox ESR 115.0, Firefox ESR 102.13, Thunderbird 115.0, and Thunderbird 102.13. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.85%

53.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 116.0
Mozilla	Firefox	>= 102.0, < 102.14
Mozilla	Firefox	>= 115.0, < 115.1
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Debian	Debian Linux	12.0

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1820587%2C1824634%2C1839235%2C1842325%2C1843847Broken Link, Issue Tracking
https://lists.debian.org/debian-lts-announce/2023/08/msg00008.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00010.htmlMailing List, Third Party Advisory
https://www.debian.org/security/2023/dsa-5464Mailing List, Third Party Advisory
https://www.debian.org/security/2023/dsa-5469Mailing List, Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2023-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-31/Vendor Advisory
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1820587%2C1824634%2C1839235%2C1842325%2C1843847Broken Link, Issue Tracking
https://lists.debian.org/debian-lts-announce/2023/08/msg00008.htmlMailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00010.htmlMailing List, Third Party Advisory
https://www.debian.org/security/2023/dsa-5464Mailing List, Third Party Advisory
https://www.debian.org/security/2023/dsa-5469Mailing List, Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2023-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-30/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-31/Vendor Advisory

Timeline

Published: Aug 1, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-4056?

How severe is CVE-2023-4056?

CVE-2023-4056 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.85% probability of exploitation in the next 30 days.

How do I fix CVE-2023-4056?

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-2023-4056?

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

Scan your code now

Source: NVD / NIST