Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read
CVSS score
5.0
EPSS probability
%0.3
Risk score
0.0
Published
4 mo ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-11850 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
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.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-11850 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | Red Hat | Red Hat Hardened Images | View |
| 2 | Red Hat | Red Hat Enterprise Linux 10 | View |
| 3 | Red Hat | Red Hat Enterprise Linux 6 | View |
| 4 | Red Hat | Red Hat Enterprise Linux 7 | View |
| 5 | Red Hat | Red Hat Enterprise Linux 8 | View |
| 6 | Red Hat | Red Hat Enterprise Linux 9 | View |
| 7 | Red Hat | Red Hat OpenShift Container Platform 4 | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.0 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H | CVE CNA |
| 5.0 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-11850 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-11850 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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