CVE-2020-3894Public exploitNetwork attack vector

Restricted-memory disclosure via AudioArray allocation race

Published Apr 1, 2020 · Updated Aug 4, 2024

A race condition in WebKit in affected Apple products allows attackers to read restricted memory through crafted web content. AudioArray::allocate shares a static padding value across threads, allowing one thread to change allocation sizing after another thread allocates and before it validates alignment, which permits out-of-bounds access. Exploitation requires WebKit to execute crafted JavaScript and win the allocation race; the demonstrated consequence is disclosure of process memory.

CVSS severity3.1
Low
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in WebKit in affected Apple products allows attackers to read restricted memory through crafted web content. AudioArray::allocate shares a static padding value across threads, allowing one thread to change allocation sizing after another thread allocates and before it validates alignment, which permits out-of-bounds access. Exploitation requires WebKit to execute crafted JavaScript and win the allocation race; the demonstrated consequence is disclosure of process memory.

The record

CVE
CVE-2020-3894
Published
Apr 1, 2020
Updated
Aug 4, 2024
Vendor
Apple
Product
iOS
Classifications
CWE-362, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <iOS 13.4 and iPadOS 13.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOSversion=unspecified <iOS 13.4 and iPadOS 13.4
Apple · iTunes for Windowsversion=unspecified <iTunes for Windows 12.10.5
Apple · Safariversion=unspecified <Safari 13.1
Apple · iCloud for Windows (Legacy)version=unspecified <iCloud for Windows 7.18
Apple · iCloud for Windowsversion=unspecified <iCloud for Windows 10.9.3
Apple · tvOSversion=unspecified <tvOS 13.4

Published CVSS scores

2.6NIST NVDAV:N/AC:H/Au:N/C:P/I:N/A:N
3.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1189Drive-by Compromise

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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