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TI-2019-09168 Aliases CVE-2019-12290GHSA-5pjp-55fh-7frw

GNU libidn2 before 2.2.0 fails to perform the roundtrip checks specified in RFC3490…

Priority LOW 39CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

GNU libidn2 before 2.2.0 fails to perform the roundtrip checks specified in RFC3490 Section 4.2 when converting A-labels to U-labels. This makes it possible in some circumstances for one domain to impersonate another. By creating a malicious domain that matches a target domain except for the inclusion of certain punycoded Unicode characters (that would be discarded when converted first to a Unicode label and then back to an ASCII label), arbitrary domains can be impersonated.

Why it matters now

EPSS 0.03225 88th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:gnu:libidn2:*:*:*:*:*:*:*:*before 2.2.0VulnerableGNU
  • cpe:2.3:a:gnu:libidn2:*:*:*:*:*:*:*:* Versions before 2.2.0 Vulnerable ·GNU

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2019-12290
  2. 2026-10-03 Alias added: GHSA-5pjp-55fh-7frw

References

Patch 2

Advisory 10

  • TI-2017-10238 Integer overflow in the decode_digit function in puny_decode.c in Libidn2 before 2.0.4… CVSS 3.1CRITICAL 9.8
  • TI-2019-13243 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 3.1CRITICAL 9.8
  • TI-2017-10237 Integer overflow in the _isBidi function in bidi.c in Libidn2 before 2.0.4 allows remote… CVSS 3.0CRITICAL 9.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences