CVE-2018-4241: An issue was discovered in certain Apple products

Q: How do I fix CVE-2018-4241?

apple tv: upgrade to 11.4; iphone os: upgrade to 11.4; mac os x: upgrade to 10.13.5. Exact commands for each OS are on this page.

Q: Is CVE-2018-4241 being exploited?

CVE-2018-4241 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2018-4241 affect?

CVE-2018-4241 affects apple tv, iphone os, mac os x. Severity is high (CVSS 7.8). An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "Kernel" component. A buffer overflow i

Q: How urgent is CVE-2018-4241?

Priority 56/100. High severity; EPSS top 5%: very likely to be exploited; Public exploit reference

This month

HIGH 7.8UPGRADEUPGRADEUPGRADE

CVE-2018-4241 is a high-severity flaw (CVSS 7.8) affecting apple tv, iphone os, mac os x. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "Kernel" component. A buffer overflow in mptcp_usr_connectx allows attackers to execute arbitrary code in a privileged context via a crafted app.

Why this priority

High severity
EPSS top 5%: very likely to be exploited
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	8.0% (top 5%)
CISA exploited list	No
Weakness	CWE-119
Published	2018-06-08
Last modified	2026-06-17

Publisher (CNA): Apple Inc. · Vendor: apple

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-06-08 18:29 UTCPublished CVE record published
2026-06-17 01:58 UTCUpdated Record last modified

apple apple tv UPGRADE

Affected: < 11.4

Fixed in: 11.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy apple-tv || rpm -q apple-tv || apple-tv --version

2. UPGRADE to 11.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade apple-tv

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade apple-tv

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

apple iphone os UPGRADE

Affected: < 11.4

Fixed in: 11.4

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple mac os x UPGRADE

Affected: < 10.13.5

Fixed in: 10.13.5

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple watchos UPGRADE

Affected: < 4.3.1

Fixed in: 4.3.1

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: XNU Kernel - Heap Overflow Due to Bad Bounds Checking in MPTCP

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-4241?

apple tv: upgrade to 11.4; iphone os: upgrade to 11.4; mac os x: upgrade to 10.13.5. Exact commands for each OS are on this page.

Is CVE-2018-4241 being exploited?

CVE-2018-4241 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-4241 affect?

CVE-2018-4241 affects apple tv, iphone os, mac os x. Severity is high (CVSS 7.8). An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "Kernel" component. A buffer overflow i

How urgent is CVE-2018-4241?

Priority 56/100. High severity; EPSS top 5%: very likely to be exploited; Public exploit reference

Software pages

iOS vulnerabilities · macOS vulnerabilities · watchOS vulnerabilities · tvOS vulnerabilities

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CVE-2018-4298 CRITICAL 9.8 UPGRADE UPGRADE In macOS High Sierra before 10.13.3, Security Update 2018-001 Sierra, and Security Update 2018-001 El Capitan,
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References

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