CVE-2025-11232
Description
A flaw was found in Kea. A remote attacker can send specific option content to the kea-dhcp4 server. When the server is configured with specific parameters, an assertion failure can be triggered and cause the kea-dhcp4 process to exit unexpectedly, resulting in a denial of service.
Statement
To exploit this issue, three configuration parameters must have the following settings:
- hostname-char-set: must have the default setting, which is "[^A-Za-z0-9.-]".
- hostname-char-replacement: must be empty, which is the default value.
- ddns-qualifying-suffix: must NOT be empty, which is not the default.
A remote and unauthenticated attacker can cause the kea-dhcp4 process to exit unexpectedly by sending specific option content, preventing all DHCP clients it servers from obtaining new leases or renewing existing ones until the service is restarted. Due to this reason, this flaw has been rated with an important severity.
Mitigation
Set the "hostname-char-replacement" parameter to any non-empty value (the default is empty). For example, setting it to "x" is an effective workaround, regardless of other settings.
...
"hostname-char-replacement": "x",
...
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the untrusted pointer is used in a read operation, an attacker might be able to read sensitive portions of memory.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the untrusted pointer references a memory location that is not accessible to the program, or points to a location that is "malformed" or larger than expected by a read or write operation, the application may terminate unexpectedly.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Modify Memory
If the untrusted pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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