What is CVE-2023-5758?

CVE-2023-5758 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-10-25.

How severe is CVE-2023-5758?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Mozilla Firefox

CVE-2023-5758

When opening a page in reader mode, the redirect URL could have caused attacker-controlled script to execute in a reflected Cross-Site Scripting (XSS) attack. This vulnerability affects Firefox for iOS < 119.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-10-25 · last modified 2026-08-19.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (35.3th percentile), scored 2026-10-05.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.3% 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
Mozilla Firefox For iOS — versions unspecified
Mozilla Firefox Mobile

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
www.mozilla.org/security/advisories/mfsa2023-48/ (Vendor Advisory)
security.gentoo.org/glsa/202401-10

Frequently asked questions

What is CVE-2023-5758?: CVE-2023-5758 is a medium-severity vulnerability in Mozilla Firefox, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-10-25.
How severe is CVE-2023-5758?: Medium severity. CVSS v3 base score is 6.1 out of 10.