CVE-2026-71196
Description
A server-side request forgery (SSRF) vulnerability was found in OpenStack Glance. The web-download image import method allows authenticated users to provide a URI from which the Glance service fetches data. Due to insufficient default host filtering, an attacker with standard tenant credentials can make Glance issue HTTP requests to arbitrary internal network hosts, including the cloud metadata service. The fetched response is stored as image data and can be downloaded by the attacker, enabling exfiltration of sensitive internal data such as cloud instance credentials.
Statement
This vulnerability is rated as Important because an authenticated tenant with the standard member role can use Glance as a full-read SSRF proxy to internal HTTP services, including cloud metadata credentials. No administrative role is required. The web-download import method is enabled by default.
Red Hat OpenStack Services on OpenShift (RHOSO) and Red Hat OpenStack Platform (RHOSP) deployments that ship OpenStack Glance with web-download enabled are affected. Deployments that have removed web-download from enabled_import_methods, or that have explicitly configured disallowed_hosts to block internal IP ranges, are not affected by the default-config path.
Mitigation
Config changes are workarounds. Upgrade to the patched Glance release.
The strongest config-only control is to disable web-download:
enabled_import_methods = glance-direct, copy-image
Setting disallowed_hosts to 127.0.0.1, 169.254.169.254, and RFC1918 addresses is only a partial workaround. It works for a direct IP in the URL. It does not stop a hostname that resolves to a blocked IP (see CVE-2026-71197). The lists accept single IPs or hostnames only, not CIDR ranges. Blocking all RFC1918 addresses is stronger than the upstream patch, which only blocks loopback and link-local. If both allowed_hosts and disallowed_hosts are set, the blacklist is ignored.
Disabling the feature is safer than host filtering.
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 | 7.7 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Red Hat CVSS v3 Score Explanation
Network-accessible full-read SSRF requiring only standard tenant credentials (member role), with cross-boundary impact on internal services including cloud metadata.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
Acknowledgements
Upstream acknowledges Cyril Roelandt (Red Hat / OpenStack Glance Core Security Team) as the original reporter.
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