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Vulnerability record · CVE-2023-28204 · published 23 June 2023

CVE-2023-28204: Apple WebKit out-of-bounds read discloses sensitive information

Apple · Safari

An out-of-bounds read in WebKit, caused by insufficient input validation, allows processing of web content to disclose sensitive information. Apple states it is aware of a report that this issue may have been actively exploited, and it affects Safari, iOS, iPadOS, macOS, watchOS, tvOS and WebKitGTK. The flaw is fixed in watchOS 9.5, tvOS 16.5, macOS Ventura 13.4, iOS/iPadOS 15.7.6 and 16.5, and Safari 16.5.

6.5 CVSS 3.1 Medium CISA KEV since 22 May 2023 EPSS 14% · top 3.5% CWE-125 · Out-of-bounds read
6.5CVSS 3.1 base score
14%EPSS exploitation probability, 30 days
YesIn CISA KEV, fix deadline passed
7Affected product versions listed by NVD
15References
17 Jun 2026Last modified by NVD

Description

An out-of-bounds read was addressed with improved input validation. This issue is fixed in watchOS 9.5, tvOS 16.5, macOS Ventura 13.4, iOS 15.7.6 and iPadOS 15.7.6, Safari 16.5, iOS 16.5 and iPadOS 16.5. Processing web content may disclose sensitive information. Apple is aware of a report that this issue may have been actively exploited.

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

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: high.

high priorityIt is listed in CISA KEV with confirmed active exploitation and a high EPSS percentile, though the CVSS impact is limited to confidentiality (6.5, medium).

What it is

An out-of-bounds read in WebKit, caused by insufficient input validation, allows processing of web content to disclose sensitive information. Apple states it is aware of a report that this issue may have been actively exploited, and it affects Safari, iOS, iPadOS, macOS, watchOS, tvOS and WebKitGTK. The flaw is fixed in watchOS 9.5, tvOS 16.5, macOS Ventura 13.4, iOS/iPadOS 15.7.6 and 16.5, and Safari 16.5.

Impact

An attacker can read out-of-bounds memory through crafted web content, potentially disclosing sensitive information from the process. There is no integrity or availability impact per the CVSS vector.

Attack surface

Reached over the network by processing malicious web content; the CVSS vector requires user interaction (UI:R) and no privileges (PR:N), so a victim must load the crafted content in a vulnerable browser or WebKit-based component.

Exploitation

CISA added this to the Known Exploited Vulnerabilities catalog on 2023-05-22 with a remediation due date of 2023-06-12, and Apple states the issue may have been actively exploited. EPSS gives a 30-day probability of 0.14292 (96.4th percentile), indicating elevated likelihood relative to other vulnerabilities.

What to do

  • Apply the vendor updates: watchOS 9.5, tvOS 16.5, macOS Ventura 13.4, iOS 15.7.6/iPadOS 15.7.6, iOS 16.5/iPadOS 16.5, and Safari 16.5.
  • Update WebKitGTK packages per the Gentoo GLSA 202401-04 advisory for Linux deployments.
  • Prioritize patching internet-facing and user-browsing endpoints, since exploitation requires only that a user process web content.
  • Track CISA KEV remediation deadlines and verify all affected Apple devices and WebKitGTK hosts are updated.
  • Where immediate patching is not possible, reduce exposure by restricting browsing of untrusted web content on unpatched systems.

Detection

  • Monitor for crashes or abnormal memory-read behavior in WebKit/Safari processes on unpatched Apple devices.
  • Hunt for known exploitation indicators associated with this CVE in web content and browser telemetry, using vendor and CISA guidance.
  • Audit asset inventories for devices still running versions prior to the fixed releases listed in the Apple advisories.
  • Review WebKitGTK host package versions against the Gentoo GLSA 202401-04 fixed versions.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.

Exploitation in the wild

CISA added CVE-2023-28204 to the Known Exploited Vulnerabilities catalog on 22 May 2023 as "Apple Multiple Products WebKit Out-of-Bounds Read Vulnerability". Required action: Apply updates per vendor instructions. Federal deadline 12 June 2023.

Affected products

7 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://security.gentoo.org/glsa/202401-04 Third Party Advisory
https://support.apple.com/en-us/HT213757 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213758 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213761 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213762 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213764 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213765 Release NotesVendor Advisory
https://security.gentoo.org/glsa/202401-04 Third Party Advisory
https://support.apple.com/en-us/HT213757 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213758 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213761 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213762 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213764 Release NotesVendor Advisory
https://support.apple.com/en-us/HT213765 Release NotesVendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-28204 US Government Resource

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Source: NIST National Vulnerability Database (record CVE-2023-28204), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.