VulnerabilityPublished 29 Sep 2025Updated 2 Apr 2026

CVE-2025-43400: Apple iOS and iPadOS · Out-of-bounds Write

Affects Apple iOS and iPadOSSource CVE Database V5

Not known to be exploited · CVSS 6.3 Medium · fixed in 18.7.1 : update Apple iOS and iPadOS when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 6.9% chance of exploitation in 30 days – higher than 94% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 18.7.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Apple iOS and iPadOS	Affected =0	Fixed in–

AI-suggested

To mitigate CVE-2025-43400, organizations should promptly deploy the security updates released by Apple for all affected platforms: iOS 18.7.1, iPadOS 18.7.1, macOS Sequoia 15.7.1, macOS Sonoma 14.8.1, macOS Tahoe 26.0.1, tvOS 26.1, visionOS 26.0.1, and watchOS 26.1. Beyond patching, organizations should implement strict controls on font file sources by restricting or scanning font files embedded in documents and emails, especially those originating from untrusted or external sources. Employing endpoint protection solutions capable of detecting anomalous font processing behavior can provide additional defense. User education to avoid opening suspicious documents or links containing fonts from unknown origins is critical. Network-level protections such as web filtering and email gateway scanning should be configured to block or quarantine potentially malicious font files. Monitoring system logs for application crashes related to font rendering can help detect exploitation attempts. Finally, organizations should maintain up-to-date backups and incident response plans to quickly recover from potential denial of service or compromise scenarios.

Description

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.1 and iPadOS 18.7.1, iOS 26.0.1 and iPadOS 26.0.1, macOS Sequoia 15.7.1, macOS Sonoma 14.8.1, macOS Tahoe 26.0.1, tvOS 26.1, visionOS 26.0.1, watchOS 26.1. Processing a maliciously crafted font may lead to unexpected app termination or corrupt process memory.

Impact

The primary impact of CVE-2025-43400 is on the availability and integrity of affected Apple devices. Exploitation can cause applications to crash unexpectedly, leading to denial of service conditions that disrupt user productivity and critical operations. Memory corruption could also be leveraged by skilled attackers to escalate the attack, potentially executing arbitrary code or bypassing security controls, although this is less certain given the medium severity rating. Organizations relying heavily on Apple ecosystems, especially in sectors where device stability and data integrity are critical (e.g., healthcare, finance, government), could face operational disruptions or targeted attacks exploiting this vulnerability. The requirement for user interaction limits automated exploitation but does not eliminate risk, especially in environments where users frequently open documents or web content from untrusted sources. Failure to patch could expose organizations to increased risk of malware delivery or system compromise via crafted font files embedded in emails, websites, or applications.

CWE-787Out-of-bounds Write (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #5
The product writes data past the end, or before the beginning, of the intended buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Apr 2026, 02:14 UTC

WeaknessesCWE-787

Technical details

References

Community reviews

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