CVE-2022-36648
Description
A NULL pointer dereference bug was found in the rocker device (emulated ethernet switch) of QEMU. The rocker_tlv_parse_nested() function could return early because of no group ids in the group_tlvs array. In such case, the tlvs pointer is NULL and tlvs[i + 1] in the next for-loop iteration ends up dereferencing a NULL pointer.
Statement
Red Hat Enterprise Linux and RHEL Advanced Virtualization are not affected by this bug, as the rocker device is not built and shipped with Red Hat qemu-kvm packages. Also, according to the QEMU upstream security guidelines [1] Red Hat Product Security does not consider this to be a vulnerability because it does not fall under the Virtualization Use Case; the rocker device is mainly used in development environments where the guest is assumed to be trusted.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 0 | 10 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Changed | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | None | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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