CVE-2019-18224: gnu libidn2 Out-of-bounds Write
CVSS: 9.8v3.1CriticalModified
AliasesALPINE-CVE-2019-18224RHBA-2019:3621UBUNTU-CVE-2019-18224DEBIAN-CVE-2019-18224DSA-4613-1CGA-2grv-wfpq-6gp5CGA-77mr-4qhq-42p2
Published 21-10-2019Last modified 14-10-2026
Vulnerability summary
CVE-2019-18224 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in gnu libidn2. EPSS estimates a 3.71% chance of exploitation in the next 30 days, higher than 89.6% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
9.8/10
010
Critical · v3.1 (NVD)EPSS score
3.71%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Advisory lineage
Upstream 0 · Downstream 5 · Related 6Timeline
- 21-10-2019PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
8 scores · 7 sources · 3 versionsCritical 9.8Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 6 agree
- OSV · AlpineEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · WolfiEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · ChainguardEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Medium 5.6Preferred score · OSV · Red hat (Ecosystem advisory) · calculated from vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:LSourcesSingle source
High 7.5Preferred score · NVD (NIST)
AV:N/AC:L/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
3.71%
Chance of exploitation in the next 30 days
Percentile
90%
Versus all other CVEs
30-day change
0.00 pp
From 3.71% on 19-09-2026
19-09-202619-10-2026
EPSS score3.71%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (bugs.chromium.org)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Redhat6 products
- idn2< 0:2.2.0-1.el8
- idn2-debuginfo< 0:2.2.0-1.el8
- libidn2< 0:2.2.0-1.el8
- libidn2-debuginfo< 0:2.2.0-1.el8
- libidn2-debugsource< 0:2.2.0-1.el8
Ubuntu2 products
- libidn2< 2.0.4-1.1ubuntu0.2
- libidn2-0All versions (No fix recorded)
Alpine1 product
- libidn2< 2.1.1-r0
Chainguard1 product
- libidn2All versions (No fix recorded)
Debian1 product
- libidn2< 2.0.5-1+deb10u1 | < 2.2.0-1
Gnu1 product
- libidn2< 2.1.1
Wolfi1 product
- libidn2All versions (No fix recorded)
7 vendors · 13 products
References
24 links- github.com/libidn/libidn2/compare/libidn2-2.1.0...libidn2-2.1.1X Refsource MISCREPORTAdvisoryRelease NotesThird Party Advisory
- github.com/libidn/libidn2/commit/e4d1558aa2c1c04a05066ee8600f37603890ba8cX Refsource MISCREPORTFIXPatchThird Party Advisory
- bugs.chromium.org/p/oss-fuzz/issues/detail?id=12420X Refsource MISCREPORTExploitIssue TrackingThird Party Advisory
- lists.opensuse.org/opensuse-security-announce/2019-12/msg00009.htmlVendor AdvisoryX Refsource SUSEWEB
- lists.opensuse.org/opensuse-security-announce/2019-12/msg00008.htmlVendor AdvisoryX Refsource SUSEWEB
