GNU Libidn vulnerabilities

6 CVEs affecting GNU Libidn, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-57053, published 2026-06-23.

Highest priority

Known exploited (CISA KEV) first, then by EPSS exploit probability.

CVE-2015-8948, published 2016-09-07. High severity, CVSS 7.5. EPSS: 6.7% chance of exploitation in the next 30 days. idn in GNU libidn before 1.33 might allow remote attackers to obtain sensitive memory information by reading a zero byte as input, which triggers an out-of-bounds read.
CVE-2016-6262, published 2016-09-07. High severity, CVSS 7.5. EPSS: 6.5% chance of exploitation in the next 30 days. idn in libidn before 1.33 might allow remote attackers to obtain sensitive memory information by reading a zero byte as input, which triggers an out-of-bounds read, a different vulnerability than…
CVE-2016-6263, published 2016-09-07. High severity, CVSS 7.5. EPSS: 3.9% chance of exploitation in the next 30 days. The stringprep_utf8_nfkc_normalize function in lib/nfkc.c in libidn before 1.33 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via crafted UTF-8 data.
CVE-2016-6261, published 2016-09-07. High severity, CVSS 7.5. EPSS: 3.9% chance of exploitation in the next 30 days. The idna_to_ascii_4i function in lib/idna.c in libidn before 1.33 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via 64 bytes of input.
CVE-2015-2059, published 2015-08-12. High severity, CVSS 7.5. EPSS: 3.2% chance of exploitation in the next 30 days. The stringprep_utf8_to_ucs4 function in libin before 1.31, as used in jabberd2, allows context-dependent attackers to read system memory and possibly have other unspecified impact via invalid UTF-8…
CVE-2026-57053, published 2026-06-23. Low severity, CVSS 2.5. EPSS: 0.1% chance of exploitation in the next 30 days. GNU libidn before 1.44 is prone to out-of-bounds reads of uninitialized memory in the ToUnicode APIs because of mishandling in idna_to_unicode_internal. The affected code is not present in libidn2.