CVE-2026-11850 (GCVE-0-2026-11850)

Vulnerability from cvelistv5 – Published: 2026-06-11 09:49 – Updated: 2026-07-06 22:00
VLAI
Title
Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read
Summary
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.
Severity
5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:25520 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-11850 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2459970 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-06-10 00:00
Credits
Red Hat would like to thank Sebastián Alba Vives for reporting this issue.
Show details on NVD website
To clipboard 

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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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