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CVE-2019-18224

30
FAUCET Score

CVE-2019-18224 describes a critical heap-based buffer overflow vulnerability in GNU libidn2 versions prior to 2.1.1, specifically within the idn2_to_ascii_4i function. This flaw, rated 9.8 CVSS (Critical), allows unauthenticated attackers to achieve high impact on confidentiality, integrity, and availability over the network with low attack complexity. While no active exploitation, public exploit code, or significant community discussion has been observed, its high severity warrants attention.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.1.1CPE matchmatch criteria
cpe:2.3:a:gnu:libidn2:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.71%
Probability of exploitation in next 30 days
EPSS Percentile
88.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0371 is in the 81st percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: libidn2-0:2.2.0-1.el8
View patch

Vendor Advisories (1)

redhatCVE-2019-18224Moderate

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

Jan 7, 2019

References

lists.opensuse.org / opensuse-security-announce/2019-12/msg00008.html
lists.opensuse.org / opensuse-security-announce/2019-12/msg00009.html
bugs.chromium.org / p/oss-fuzz/issues/detail
ExploitIssue TrackingThird Party Advisory
github.com / libidn/libidn2/commit/e4d1558aa2c1c04a05066ee8600f37603890ba8c
PatchThird Party Advisory
github.com / libidn/libidn2/compare/libidn2-2.1.0...libidn2-2.1.1
Release NotesThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/JDQVQ2XPV5BTZUFINT7AFJSKNNBVURNJ
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/MINU5RKDFE6TKAFY5DRFN3WSFDS4DYVS
seclists.org / bugtraq/2020/Feb/4
security.gentoo.org / glsa/202003-63
usn.ubuntu.com / 4168-1
debian.org / security/2020/dsa-4613