Back Linuxsecurity

Fedora 43 libidn Critical Out-of-bounds Exploit CVE-2026

Linuxsecurity •LinuxSecurity Advisories • August 12, 2026

Share: View original

Audit Linux privileges now to limit compromise, escalation, and system-wide damage. Review Linux Privileges ×

GNU Libidn is an implementation of the Stringprep, Punycode and

IDNA specifications defined by the IETF Internationalized Domain

Names (IDN) working group, used for internationalized domain

Security fix for CVE-2026-57053.

* Mon Jun 22 2026 Miroslav Lichvar - 1.44-1 - update to 1.44 * Fri Jan 16 2026 Fedora Release Engineering - 1.43-4 - Rebuilt for * Wed Oct 1 2025 Yaakov Selkowitz - 1.43-3 - Rebuilt for java-25-openjdk as system jdk

[ 1 ] Bug #2509779 - CVE-2026-57053 libidn: GNU libidn: Out-of-bounds read in ToUnicode APIs [fedora-all]

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-acf66846ee' at the command line. For more information, refer to the dnf documentation available at

Get the latest Linux and open source security news straight to your inbox.

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Out-of-Bounds Vulnerability in GNU Libidn Affects Fedora Systems A critical out-of-bounds vulnerability, CVE-2026-57053, has been identified in the GNU Libidn library, which is used in Fedora systems for internationalized domain names. The vulnerability allows for out-of-bounds reads in the ToUnicode APIs, potentially leading to information disclosure. Affected versions include libidn 1.43-3 and earlier, with updates released on June 22, 2026, for Fedora 43 and June 23, 2026, for mingw-libidn. Users are advised to audit their Linux privileges to prevent escalation and system-wide damage. The vulnerability was published on June 23, 2026, and is being addressed through security updates. Administrators can apply the updates using the 'dnf' package manager. The current status indicates that the vulnerability is critical, and immediate action is recommended. 3 sources 73

Extracted Entities

Fedora 43 libidn Critical Out-of-bounds Exploit CVE-2026

The full story

Extracted Entities

CVEs (1)

CWE Weaknesses (1)

Platforms (1)