CVE-2026-11850

Publication date 11 June 2026

Last updated 6 August 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.0 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
krb5 26.04 LTS resolute
Fixed 1.22.1-2ubuntu4.1
25.10 questing Ignored end of life, was needs-triage
24.04 LTS noble
Fixed 1.20.1-6ubuntu2.7
22.04 LTS jammy
Fixed 1.19.2-2ubuntu0.8
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

Patch details

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Package Patch details
krb5

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.0 · Medium

Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-8585-1
    • Kerberos vulnerabilities
    • 22 July 2026

Other references

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