{"id":"DEBIAN-CVE-2026-11850","details":"An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data.","modified":"2026-09-14T17:01:41.865010214Z","published":"2026-06-11T10:16:21.217Z","upstream":["CVE-2026-11850"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-11850"}],"affected":[{"package":{"name":"krb5","ecosystem":"Debian:12","purl":"pkg:deb/debian/krb5?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.20.1-2","1.20.1-2+deb12u1","1.20.1-2+deb12u2","1.20.1-2+deb12u3","1.20.1-2+deb12u4","1.20.1-2+deb12u5","1.20.1-2+loong64","1.20.1-3","1.20.1-4","1.20.1-5","1.20.1-5.1","1.20.1-5.1~exp1","1.20.1-6","1.21.2-1","1.21.3-1","1.21.3-2","1.21.3-3","1.21.3-4","1.21.3-5","1.22.1-1","1.22.1-2","1.22.1-2.1","1.22.1-3"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"}},{"package":{"name":"krb5","ecosystem":"Debian:13","purl":"pkg:deb/debian/krb5?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.21.3-5","1.21.3-5+deb13u1","1.22.1-1","1.22.1-2","1.22.1-2.1","1.22.1-3"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"}},{"package":{"name":"krb5","ecosystem":"Debian:14","purl":"pkg:deb/debian/krb5?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.22.1-3"}]}],"versions":["1.21.3-5","1.22.1-1","1.22.1-2","1.22.1-2.1"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H"}]}