CVE-2026-105648 in Ghost
Summary
by MITRE • 10/06/2026
Ghost is a Node.js content management system. From 6.0.9 until 6.65.0, a validation issue allowed some functionality, such as Webmentions, to be abused by an unauthenticated user to make limited HTTP requests to hosts in the Ghost server's internal network on some network configurations. A successful attack would not result in any response data being returned. This issue is fixed in version 6.65.0.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified within the Ghost content management system, specifically affecting versions from 6.0.9 through 6.65.0, represents a significant server-side request forgery risk rooted in insufficient input validation. As an open-source publishing platform widely deployed for blogs and media sites, Ghost relies on various integrations to function correctly, including the Webmentions feature which allows other websites to notify Ghost when they link back or reference content hosted there. The core technical flaw lies in how the application processes incoming requests related to these integrations without adequately restricting the destination of outbound network connections initiated by the server itself. This lack of strict validation on the target host parameter enables an unauthenticated attacker to manipulate the request logic, forcing the Ghost server to act as a proxy or relay for HTTP traffic directed at internal network addresses that would otherwise be inaccessible from the public internet.
From a technical perspective, this vulnerability aligns with CWE-918, which describes Server-Side Request Forgery (SSRF). The attacker exploits the application's legitimate functionality by crafting specific requests to endpoints such as those handling Webmentions. Because the server is configured to make outbound calls on behalf of users or integrations, it bypasses standard perimeter security controls that typically block direct access from external networks to internal subnets like 10.x.x.x, 172.16.x.x, or 192.168.x.x. The operational impact is nuanced; while the attacker cannot directly receive response data due to how the underlying HTTP client handles the return stream in this specific implementation, the ability to initiate connections to internal services can still be highly detrimental. This capability allows for network reconnaissance, where an attacker can determine which ports are open and what services are running on internal hosts by observing differences in connection timeouts or error messages returned during the handshake phase of TCP communication.
The security implications extend beyond mere port scanning. In many modern deployment architectures, particularly those utilizing containerization or microservices, internal services often communicate over unencrypted HTTP protocols without mutual TLS authentication. By forcing the Ghost server to connect to these internal endpoints, an attacker can potentially trigger unintended actions on other services within the same network segment. For instance, if there are administrative interfaces for databases, monitoring tools like Prometheus or Grafana, or configuration management systems accessible only from the application layer, this SSRF vector could serve as a pivot point. Although no response data is returned to the attacker directly, the side effects of these requests can include triggering background jobs, causing denial-of-service conditions on internal resources by flooding them with connection attempts, or interacting with vulnerable services that do not require authentication for certain administrative actions.
This vulnerability maps closely to MITRE ATT&CK technique T1598, specifically Stealing Web Content via Server-Side Request Forgery, although in this case the exploitation is limited to reconnaissance and potential service disruption rather than data exfiltration due to the lack of response reflection. It also relates to T1046, Network Service Discovery, as the attacker can map out the internal network topology by probing various IP addresses and ports through the compromised Ghost instance. The absence of a return channel for payload data mitigates some risks but does not eliminate the threat landscape associated with SSRF vulnerabilities in server-side applications.
To mitigate this vulnerability, organizations running affected versions of Ghost must upgrade immediately to version 6.65.0 or later, where the validation logic has been corrected to enforce strict allow-listing of permitted outbound destinations and reject requests targeting internal IP ranges. For environments that cannot patch immediately due to dependency constraints, network-level controls should be implemented. This includes configuring firewalls to block outgoing HTTP traffic from Ghost server IPs to private address spaces unless explicitly required for specific external integrations. Additionally, implementing egress filtering rules that restrict the application layer protocols allowed on outbound connections can reduce the attack surface. It is also advisable to isolate content management systems in a dedicated DMZ or subnet with strict ingress and egress policies, ensuring that even if an SSRF vulnerability exists, its ability to reach sensitive internal assets remains severely limited by network segmentation rather than relying solely on application-level validation.