AI Threat AlertCVE-2026-11850
MEDIUMAn 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...
Full CISO analysis pending enrichment.
What systems are affected?
How severe is it?
What is the attack surface?
What should I do?
No patch available
Monitor for updates. Consider compensating controls or temporary mitigations.
Which compliance frameworks are affected?
Compliance analysis pending. Sign in for full compliance mapping when available.
Frequently Asked Questions
What is CVE-2026-11850?
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.
Is CVE-2026-11850 actively exploited?
No confirmed active exploitation of CVE-2026-11850 has been reported, but organizations should still patch proactively.
How to fix CVE-2026-11850?
No patch is currently available. Monitor vendor advisories for updates.
What is the CVSS score for CVE-2026-11850?
CVE-2026-11850 has a CVSS v3.1 base score of 5.0 (MEDIUM).
What are the technical details?
Original Advisory
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.
Weaknesses (CWE)
CWE-191 — Integer Underflow (Wrap or Wraparound): The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.
Source: MITRE CWE corpus.
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:HReferences
- access.redhat.com/errata/RHSA-2026:25520vendor-advisoryx_refsource_REDHAT
- access.redhat.com/security/cve/CVE-2026-11850vdb-entryx_refsource_REDHAT
- bugzilla.redhat.com/show_bug.cgiissue-trackingx_refsource_REDHAT
Timeline
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