CVE-2026-11850mediumCWE-191

CVE-2026-11850: medium-severity vulnerability in Red Hat Enterprise Linux 10

Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5epss 0.3%
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.
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
Affected products
Red Hat · Red Hat Enterprise Linux 10Red Hat · Red Hat Enterprise Linux 6Red Hat · Red Hat Enterprise Linux 7Red Hat · Red Hat Enterprise Linux 8Red Hat · Red Hat Enterprise Linux 9Red Hat · Red Hat Hardened ImagesRed Hat · Red Hat OpenShift AI (RHOAI)Red Hat · Red Hat OpenShift Container Platform 4Red Hat · Red Hat OpenShift Container Platform 5
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