CVE-2026-11850: Red Hat Enterprise Linux 10

Medium severity, CVSS 5.0. EPSS: 0.3% chance of exploitation in the next 30 days.

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 < 2, triggering the underflow when the KDC or kadmind reads principal data.

Affected products

• Red Hat Red Hat Enterprise Linux 10
• Red Hat Red Hat Enterprise Linux 6
• Red Hat Red Hat Enterprise Linux 7
• Red Hat Red Hat Enterprise Linux 8
• Red Hat Red Hat Enterprise Linux 9
• Red Hat Red Hat Hardened Images: before 1.22.2-8.hum1 (fixed in 1.22.2-8.hum1)
• Red Hat Red Hat Openshift Container Platform 4

Published 2026-06-11. Last modified 2026-08-31.