CVE-2025-43400Network attack vector

App termination or memory corruption via crafted fonts

Published Sep 29, 2025 · Updated Apr 2, 2026

Out-of-bounds writing in Apple operating systems allows remote attackers to terminate apps or corrupt process memory via a crafted font. FontParser fails to enforce buffer boundaries while parsing font data, allowing crafted values to drive a write outside the intended allocation. Exploitation requires the target to process attacker-supplied font content; published impact is limited to application termination or corruption of the affected process's memory.

CVSS severity6.3
Medium
EPSS probability6.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds writing in Apple operating systems allows remote attackers to terminate apps or corrupt process memory via a crafted font. FontParser fails to enforce buffer boundaries while parsing font data, allowing crafted values to drive a write outside the intended allocation. Exploitation requires the target to process attacker-supplied font content; published impact is limited to application termination or corruption of the affected process's memory.

The record

CVE
CVE-2025-43400
Published
Sep 29, 2025
Updated
Apr 2, 2026
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-787, T1203, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record 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=0 <18.7.1
  2. Affected versionversion=0 <26.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=0 <18.7.1; version=0 <26.0.1
Apple · visionOSversion=0 <26.0.1
Apple · tvOSversion=0 <26.1
Apple · macOSversion=0 <14.8.1; version=0 <15.7.1; version=0 <26.0.1
Apple · watchOSversion=0 <26.1

Published CVSS scores

6.3GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution
T1204.002Malicious File

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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