Description
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.
Published: 2026-06-11
Score: 5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

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History

Fri, 12 Jun 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat hardened Images
Redhat openshift Container Platform
Vendors & Products Redhat hardened Images
Redhat openshift Container Platform

Fri, 12 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
References

Fri, 12 Jun 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Thu, 11 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 11 Jun 2026 10:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-191
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H'}


Subscriptions

Redhat Enterprise Linux Hardened Images Hummingbird Openshift Openshift Container Platform
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-06-18T16:05:36.425Z

Reserved: 2026-06-10T08:12:34.560Z

Link: CVE-2026-11850

cve-icon Vulnrichment

Updated: 2026-06-11T12:36:51.179Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-06-11T10:16:21.217

Modified: 2026-06-12T15:16:24.737

Link: CVE-2026-11850

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-06-10T00:00:00Z

Links: CVE-2026-11850 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T20:18:19Z

Weaknesses