An integer underflow vulnerability was found in MIT krb5 in the berval2tldata() function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c.
CVE-2026-11850
An integer underflow vulnerability was found in MIT krb5 in the berval2tldata() function in plugins/kdb/ldap/libkdbldap/ldapprincipal2.c. The function performs an unsigned subtraction (bvlen - 2) without a prior bounds check. When bvlen is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16t, 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 bvlen < 2, triggering the underflow when the KDC or kadmind reads principal data.
Assessment
- CVSS
- 5 (v3.1)
- Severity
- Medium
- EPSS
- 0.27% chance of exploitation in the next 30 days
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 11 June 2026
- Last updated
- 31 October 2026
- Affected
- Red Hat
- Assigner
- redhat
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
At the source
References
Community proofs of concept
No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.
Submit a proof of concept
Only for publicly disclosed vulnerabilities, and only material from testing you were authorised to perform. This platform does not buy, sell, or broker exploits — see earning from vulnerability research for legitimate bounty programs. Submissions are reviewed before they appear. Text only; do not include live credentials, personal data, or anything targeting systems you are not permitted to test.
Query this programmatically
Agents can read this through the MCP endpoint, or over HTTP:
curl https://cve.zerocrew.in/api/cve/CVE-2026-11850