CVE-2020-3856

Heap corruption via malformed libxpc strings

Published Feb 27, 2020 · Updated Aug 4, 2024

Memory corruption in Apple libxpc allows local users to corrupt heap memory when an affected device processes a crafted string. Apple identifies inadequate input validation in libxpc string processing as the wrong operation, but has not disclosed the responsible function or parsing logic. Successful exploitation requires local execution and user interaction; public records establish heap corruption but do not identify a reliable code-execution outcome.

CVSS severity7.8
High
EPSS probability0.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Apple libxpc allows local users to corrupt heap memory when an affected device processes a crafted string. Apple identifies inadequate input validation in libxpc string processing as the wrong operation, but has not disclosed the responsible function or parsing logic. Successful exploitation requires local execution and user interaction; public records establish heap corruption but do not identify a reliable code-execution outcome.

The record

CVE
CVE-2020-3856
Published
Feb 27, 2020
Updated
Aug 4, 2024
Vendor
Apple
Product
iOS
Classifications
CWE-787, CWE-20, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 27, 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

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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=unspecified <iOS 13.3.1 and iPadOS 13.3.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOSversion=unspecified <iOS 13.3.1 and iPadOS 13.3.1
Apple · tvOSversion=unspecified <tvOS 13.3.1
Apple · macOSversion=unspecified <macOS Catalina 10.15.3
Apple · watchOSversion=unspecified <watchOS 6.1.2

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NVDAV:N/AC:M/Au:N/C:C/I:C/A:C

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-20Improper Input Validation
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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