Public proof of conceptFix available

CVE-2018-4124

Q: Is CVE-2018-4124 actively exploited?

Active exploitation of CVE-2018-4124 has not been confirmed. Its EPSS score was 5.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2018-4124?

CVE-2018-4124 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2018-04-03
Fixed in11.2.6
WeaknessCWE-119

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

An issue was discovered in certain Apple products. iOS before 11.2.6 is affected. macOS before 10.13.3 Supplemental Update is affected. tvOS before 11.2.6 is affected. watchOS before 4.2.3 is affected. The issue involves the "CoreText" component. It allows remote attackers to cause a denial of service (memory corruption and system crash) or possibly have unspecified other impact via a crafted string containing a certain Telugu character.

Timeline

dates in UTC

2018-04-0306:29CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2018-4124?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2018-4124?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apple iphone os

Branch	Affected	Fixed in	Source
11.2	< 11.2.6	11.2.6	NVD

Apple mac os x

Branch	Affected	Fixed in	Source
10.13	< 10.13.3	10.13.3	NVD

Apple tvos

Branch	Affected	Fixed in	Source
11.2	< 11.2.6	11.2.6	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apple iphone os to 11.2.6

Advisories and patches

support.apple.comVendor Advisory
support.apple.comVendor Advisory
support.apple.comVendor Advisory
support.apple.comVendor Advisory

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedjamf/TELUGU_CVE-2018-4124_POC

Sources

NVDCVSS 3.09.8read 2026-10-23
NVDCVSS 2.09read 2026-10-23
NVDweakness (CWE)CWE-119read 2026-10-23
FIRST EPSSEPSS score5.9 %2026-10-22
PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2018-04-03
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2018-4124?

Is CVE-2018-4124 actively exploited?

Active exploitation of CVE-2018-4124 has not been confirmed. Its EPSS score was 5.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-4124?

CVE-2018-4124 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database