CVE-2023-39928Public exploitNetwork attack vector

Code execution via MediaRecorder lock lifetime error

Published Oct 6, 2023 · Updated Nov 4, 2025

Use-after-free in Apple WebKit's GStreamer MediaRecorder before 2.42.0 allows remote attackers to execute code via malicious web content. A completion callback can destroy MediaRecorderPrivateGStreamer while fetchData still holds a Locker for m_dataLock, causing the Locker destructor to write to freed storage. Exploitation requires a user to visit a crafted page that starts and stops MediaRecorder, and success can corrupt memory or execute code in the content process.

CVSS severity8.8
High
EPSS probability1.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Apple WebKit's GStreamer MediaRecorder before 2.42.0 allows remote attackers to execute code via malicious web content. A completion callback can destroy MediaRecorderPrivateGStreamer while fetchData still holds a Locker for m_dataLock, causing the Locker destructor to write to freed storage. Exploitation requires a user to visit a crafted page that starts and stops MediaRecorder, and success can corrupt memory or execute code in the content process.

The record

CVE
CVE-2023-39928
Published
Oct 6, 2023
Updated
Nov 4, 2025
Vendor
Apple
Product
WebKit
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=WebKitGTK 2.40.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · WebKitversion=WebKitGTK 2.40.5

Published CVSS scores

8.8Cisco TalosCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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