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.
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.
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History
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 |
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| 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 |
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| Vendors & Products |
Redhat
Redhat enterprise Linux Redhat hummingbird Redhat openshift |
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| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: redhat
Published:
Updated: 2026-06-11T12:37:05.721Z
Reserved: 2026-06-10T08:12:34.560Z
Link: CVE-2026-11850
No data.
Status : Received
Published: 2026-06-11T10:16:21.217
Modified: 2026-06-11T10:16:21.217
Link: CVE-2026-11850
No data.
OpenCVE Enrichment
Updated: 2026-06-11T11:30:06Z
Weaknesses