CVE-2026-28295
Description
A flaw was found in the FTP GVfs backend. A malicious FTP server can exploit this vulnerability by providing an arbitrary IP address and port in its passive mode (PASV) response. The client unconditionally trusts this information and attempts to connect to the specified endpoint, allowing the malicious server to probe for open ports accessible from the client's network.
Statement
This is a LOW impact information disclosure flaw in the GVfs FTP backend. A client connecting to a malicious FTP server could be coerced into probing for open ports accessible from the client's network, as the client unconditionally trusts the IP address and port provided in passive mode (PASV) responses. This vulnerability requires user interaction with a compromised or malicious FTP server.
Mitigation
To mitigate this issue, users should avoid connecting to untrusted or unknown FTP servers when using applications that rely on the GVfs FTP backend. This vulnerability requires the client to interact with a malicious FTP server for exploitation.
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 | 4.3 | N/A | 4.3 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
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
Red Hat would like to thank Codean Labs for reporting this issue.
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