What is CVE-2023-4580?

CVE-2023-4580 is a medium-severity vulnerability in Mozilla Firefox, classified under Missing Encryption of Sensitive Data. CVSS score: 6.5/10. Published 2023-09-11.

How severe is CVE-2023-4580?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Mozilla Firefox

CVE-2023-4580

Push notifications stored on disk in private browsing mode were not being encrypted potentially allowing the leak of sensitive information. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

Published 2023-09-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (34.2th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 34.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Mozilla Firefox — versions unspecified
Mozilla Firefox Esr — versions unspecified
Mozilla Firefox Esr
Mozilla Thunderbird — versions unspecified

Weakness classification (CWE)

CWE-311 — Missing Encryption of Sensitive Data

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
www.mozilla.org/security/advisories/mfsa2023-34/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2023-36/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2023-38/ (Vendor Advisory)

Frequently asked questions

What is CVE-2023-4580?: CVE-2023-4580 is a medium-severity vulnerability in Mozilla Firefox, classified under Missing Encryption of Sensitive Data. CVSS score: 6.5/10. Published 2023-09-11.
How severe is CVE-2023-4580?: Medium severity. CVSS v3 base score is 6.5 out of 10.