Source: krb5 X-Debbugs-CC: [email protected] Severity: important Tags: security
Hi, The following vulnerability was published for krb5. CVE-2026-11850[0]: | 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. https://krbdev.mit.edu/rt/Ticket/Display.html?id=9206 https://github.com/krb5/krb5/commit/2a5fd83d4436583f2ddc0e193269a4d800ee45c4 If you fix the vulnerability please also make sure to include the CVE (Common Vulnerabilities & Exposures) id in your changelog entry. For further information see: [0] https://security-tracker.debian.org/tracker/CVE-2026-11850 https://www.cve.org/CVERecord?id=CVE-2026-11850 Please adjust the affected versions in the BTS as needed.
