CVE-2026-63045
Description
A flaw was found in httpd. When configured as a forward proxy using the mod_proxy_ftp module, the server improperly validates the network address returned in a File Transfer Protocol (FTP) passive mode (PASV) response. A malicious FTP server can exploit this flaw by returning a crafted reply, forcing the proxy to establish a data connection to an arbitrary third-party host. This issue may allow an attacker to initiate unauthorized network connections or probe internal systems that are otherwise inaccessible.
Mitigation
Disable the mod_proxy_ftp module or ensure forward proxying is disabled in the Apache HTTP Server configuration.
1. Comment out the mod_proxy_ftp module load line in `/etc/httpd/conf.modules.d/00-proxy.conf`:
# LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
2. Ensure forward proxying is turned off in `/etc/httpd/conf/httpd.conf`:
ProxyRequests Off
3. Reload the httpd service to apply changes:
systemctl reload httpd
Caveat: Disabling mod_proxy_ftp terminates the ability of httpd to proxy FTP requests.
Warning: Reloading or restarting the httpd service will briefly affect active connections while configuration changes are reloaded.
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 | 5.3 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| 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:N/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.
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