CVE-2021-40085
Description
An input-validation flaw was found in openstack-neutron, where an authenticated attacker could change the dnsmasq configuration. By crafting extra_dhcp_opts values, the attacker could crash the dnsmasq, change parameters for tenants sharing the same interface, or otherwise alter that daemon’s behavior. This flaw might also be used to trigger a configuration parsing buffer overflow in versions of dnsmasq prior to 2.81. The highest threat from this vulnerability is to system availability, but also threatens data confidentiality and integrity.
Statement
IMPORTANT impact affects Red Hat OpenStack Platform deployments using openstack-neutron. An authenticated attacker can submit crafted extra_dhcp_opts values to alter the dnsmasq configuration, crash the service, or change parameters for other tenants sharing the same interface. The input may also trigger a configuration-parsing buffer overflow in dnsmasq versions before 2.81, potentially leading to remote code execution. The highest threat is to system availability, with lower impacts to confidentiality and integrity. The current affects data also identifies Community Projects as affected, while entries for Red Hat OpenStack Platform 16.2, 17.1, and 18.0, and Red Hat build of Apache Camel, are marked not affected because the vulnerable code is not present. For affected Red Hat OpenStack Platform streams marked DELEGATED, a fix is being pursued.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 | 7.6 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | None | N/A |
| Integrity Impact | Low | High | N/A |
| Availability Impact | High | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Acknowledgements
Red Hat would like to thank the OpenStack project for reporting this issue.
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