CVE-2021-3594
Description
An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality.
Statement
This flaw affects the versions of SLiRP embedded in qemu-kvm as shipped with Red Hat Enterprise Linux 8 and RHEL Advanced Virtualization. A future update may address this issue. It is worth noting that although qemu-kvm is built with SLiRP networking support, due to its limitations, it is not used by the virtual machine guests by default.
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 | 3.8 | 3.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
Acknowledgements
Red Hat would like to thank Agustin Gianni (GitHub Security Lab) for reporting this issue.
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