What is CVE-2016-4604?

CVE-2016-4604 is a medium-severity vulnerability in Apple Iphone OS, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.4/10. Published 2016-07-22.

How severe is CVE-2016-4604?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Open Redirect in Apple Iphone OS

CVE-2016-4604

Safari in Apple iOS before 9.3.3 allows remote attackers to spoof the displayed URL via an HTTP response specifying redirection to an invalid TCP port number.

Vulnerability class: Open Redirect

Published 2016-07-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.012 (67.4th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 67.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

www.securitytracker.com/id/1036344 (vdb-entry)
lists.apple.com/archives/security-announce/2016/Jul/msg00001.html (vendor-advisory, Mailing List)
www.securityfocus.com/bid/91825 (vdb-entry)
support.apple.com/HT206902 (Vendor Advisory)

Frequently asked questions

What is CVE-2016-4604?: CVE-2016-4604 is a medium-severity vulnerability in Apple Iphone OS, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.4/10. Published 2016-07-22.
How severe is CVE-2016-4604?: Medium severity. CVSS v3 base score is 5.4 out of 10.