CVE-2026-108770 in Appwrite
Summary
by MITRE • 10/12/2026
A weakness has been identified in Appwrite up to 2.3.0. This vulnerability affects the function PublicHostname of the file src/Appwrite/Platform/Modules/Avatars/Http/Screenshots/Get.php of the component Browser Screenshot Service. This manipulation of the argument url causes server-side request forgery. The attack can be initiated remotely. Upgrading to version 2.4.0 is able to resolve this issue. Patch name: 393255e7302ae5503331d45802e2eee01c6a47fe. You should upgrade the affected component.
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Analysis
by VulDB Data Team • 10/12/2026
The Appwrite platform, a comprehensive backend-as-a-service solution for web and mobile applications, contains a critical server-side request forgery vulnerability in its Browser Screenshot Service prior to version 2.4.0. This flaw resides specifically within the PublicHostname function located in the src/Appwrite/Platform/Modules/Avatars/Http/Screenshots/Get.php file. The vulnerability arises from insufficient validation of user-supplied input passed as the url argument, allowing an attacker to manipulate this parameter into directing internal application logic toward arbitrary destinations rather than intended public endpoints. This lack of strict allowlisting or sanitization creates a classic injection point where external control over URL resolution can be exercised by remote actors without requiring authentication in many configurations, fundamentally undermining the trust boundary between client requests and server-side resource access.
From a technical perspective, this vulnerability is categorized under CWE-918 Server-Side Request Forgery (SSRF), which describes weaknesses that allow an attacker to cause the server to make HTTP requests to arbitrary domains or IP addresses. By exploiting this flaw, an adversary can leverage the application's network privileges to probe internal services, access cloud metadata endpoints such as those found in AWS EC2 or Google Cloud Platform, or interact with other backend microservices that are not exposed to the public internet but remain reachable from within the Appwrite deployment environment. The attack vector is remote and potentially unauthenticated depending on the specific configuration of the avatar screenshot feature, making it a high-risk entry point for further network reconnaissance and lateral movement within the infrastructure hosting the application.
The operational impact of this vulnerability extends beyond simple data exfiltration to include potential compromise of internal service integrity and credential theft through metadata access. Attackers can use the forged requests to map out the internal network topology, identify vulnerable services running on private subnets, or attempt to trigger actions within other connected systems that rely on implicit trust relationships with Appwrite servers. In cloud environments specifically, accessing instance metadata endpoints could lead to the retrieval of temporary security credentials, IAM roles, and configuration details, which would grant the attacker significant control over the underlying infrastructure. This transforms a seemingly benign feature handling avatar screenshots into a powerful tool for deep infrastructure penetration.
To mitigate this risk immediately, organizations running Appwrite versions up through 2.3.0 must upgrade to version 2.4.0 or later as soon as possible. The patch identified by commit hash 393255e7302ae5503331d45802e2eee01c6a47fe addresses the input validation logic within the PublicHostname function, ensuring that only whitelisted or properly sanitized URLs are processed. Until an upgrade is performed, administrators should consider restricting outbound network traffic from Appwrite servers to known internal and external endpoints using firewall rules as a compensating control. Additionally, monitoring logs for unusual outbound connection patterns originating from the screenshot service can help detect active exploitation attempts in real-time. Aligning with MITRE ATT&CK framework techniques such as T1583 Acquire Infrastructure or T1071 Application Layer Protocol depending on how the SSRF is leveraged further emphasizes the need for robust network segmentation and strict egress filtering to limit the blast radius of any successful exploitation.