CVE-2023-5174

Name: CVE-2023-5174
Creator: NVD / NIST
Published: 2023-09-27T15:19:42.457+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.99%

Last modified Jun 17, 2026

CVE-2023-5174 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. If Windows failed to duplicate a handle during process creation, the sandbox code may have inadvertently freed a pointer twice, resulting in a use-after-free and a potentially exploitable crash. *This bug only affects Firefox on Windows when run in non-standard configurations (such as using `runas`). Other operating systems are unaffected.* This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.. EPSS estimates a 0.99% chance of exploitation in the next 30 days.

Description

If Windows failed to duplicate a handle during process creation, the sandbox code may have inadvertently freed a pointer twice, resulting in a use-after-free and a potentially exploitable crash. *This bug only affects Firefox on Windows when run in non-standard configurations (such as using `runas`). Other operating systems are unaffected.* This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

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

0.99%

58.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 118
Mozilla	Firefox Esr	< 115.3
Mozilla	Thunderbird	< 115.3

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1848454Permissions Required
https://www.mozilla.org/security/advisories/mfsa2023-41/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-42/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-43/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1848454Permissions Required
https://www.mozilla.org/security/advisories/mfsa2023-41/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-42/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2023-43/Vendor Advisory

Timeline

Published: Sep 27, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-5174?

How severe is CVE-2023-5174?

CVE-2023-5174 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.99% probability of exploitation in the next 30 days.

How do I fix CVE-2023-5174?

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-2023-5174?

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

Scan your code now

Source: NVD / NIST