CVE-2023-5173

Name: CVE-2023-5173
Creator: NVD / NIST
Published: 2023-09-27T15:19:42.34+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.73%

Last modified Jun 17, 2026

CVE-2023-5173 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In a non-standard configuration of Firefox, an integer overflow could have occurred based on network traffic (possibly under influence of a local unprivileged webpage), leading to an out-of-bounds write to privileged process memory. *This bug only affects Firefox if a non-standard preference allowing non-HTTPS Alternate Services (`network.http.altsvc.oe`) is enabled.* This vulnerability affects Firefox < 118.. EPSS estimates a 0.73% chance of exploitation in the next 30 days.

Description

In a non-standard configuration of Firefox, an integer overflow could have occurred based on network traffic (possibly under influence of a local unprivileged webpage), leading to an out-of-bounds write to privileged process memory. *This bug only affects Firefox if a non-standard preference allowing non-HTTPS Alternate Services (`network.http.altsvc.oe`) is enabled.* This vulnerability affects Firefox < 118.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.73%

49.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-190

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 118

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1823172Permissions Required
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-41/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1823172Permissions Required
https://security.gentoo.org/glsa/202401-10
https://www.mozilla.org/security/advisories/mfsa2023-41/Vendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2023-5173?

How severe is CVE-2023-5173?

CVE-2023-5173 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.73% probability of exploitation in the next 30 days.

How do I fix CVE-2023-5173?

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-2023-5173?

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

Scan your code now

Source: NVD / NIST