PT-2026-31812 · Libidn2 · Libidn2

Zou Dikai · Published 2026-04-09 · Updated 2026-04-10 · CVE-2026-5772

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions versions prior to 2.3

Description A 1-byte stack buffer over-read exists in the MatchDomainName function (src/internal.c) during wildcard hostname validation when the LEFT MOST WILDCARD ONLY flag is active. If a wildcard * exhausts the entire hostname string, the function reads one byte past the buffer without a bounds check, potentially causing a crash.

Recommendations Update to version 2.3 or later.

Fix

Buffer Over-read

Weakness Enumeration

CWE-126

Related Identifiers

CVE-2026-5772

Affected Products

Libidn2

References · 9

• https://github.com/wolfSSL/wolfssl/pull/10119 · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-5772 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-5772 · Security Note
• https://ubuntu.com/security/CVE-2026-5772 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-5772 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-5772 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-5772 · Vendor Advisory
• https://twitter.com/CVEnew/status/2042364278263411100 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2042395371041694110 · Twitter Post