Skip to main content
CRITICAL

CVE-2019-18224

CVSS v3

9.8

CRITICAL

EPSS Score

3.7 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Get an alert for each new CVE published for libidn2.

Set up CVE WatchFree account · no credit card

Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2019-18224 Red Hat Product Security57 products fixed

    libidn2: heap-based buffer overflow in idn2_to_ascii_4i in lib/lookup.c

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5

  • RHBA-2019:3621 Red Hat Product Security57 products fixed

    Red Hat Bug Fix Advisory: libidn2 bug fix and enhancement update

Full record on NVD

Description

idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

Technical details

Published
2019-10-21

Frequently asked questions

What is CVE-2019-18224?

idn2_to_ascii_4i in lib/lookup.c in GNU libidn2 before 2.1.1 has a heap-based buffer overflow via a long domain string.

Is CVE-2019-18224 actively exploited?

Active exploitation of CVE-2019-18224 has not been confirmed. Its EPSS score was 3.7% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-18224?

CVE-2019-18224 has a CVSS v3 base score of 9.8 (CRITICAL severity).

Running libidn2? Hear about its next vulnerability

CVE Watch matches each new CVE to the vendors and products you list (vendor and product, not the version) and puts it in your alerts with its KEV and EPSS status.

Get alerts for this productCISA KEV additions, October 2026Search CVEs

Already have an account? Open CVE WatchNo credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

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

Back to CVE Database