Server-Side Request Forgery in Mosaxiv Clawlet

Executive Summary

CVE-2026-15619 is a Server-Side Request Forgery (SSRF) vulnerability in the mosaxiv clawlet software, specifically in versions up to and including 0.2.10. The issue exists in the `web_fetch` function located in the file `tools/tool_web_fetch.go`.

The vulnerability allows an attacker to manipulate the `url` argument passed to the `web_fetch` function, causing the application to make unauthorized outbound HTTP/HTTPS requests. This occurs because the default web policy in `tools/web_fetch_policy.go` permits requests to all domains (using a wildcard `*`) and does not properly validate or block special-use IPv4 addresses or non-global IP ranges.

For example, an attacker could craft a request to an internal or non-public IP address (e.g., `http://198.18.0.1:18080/internal`), which the application would then attempt to access. This could expose internal services, cloud metadata endpoints, or other sensitive resources reachable from the runtime environment.

The vulnerability is exploitable remotely and has been publicly disclosed, including a proof-of-concept (PoC). The GitHub issue associated with this CVE was closed with the label 'not planned,' indicating no immediate patch is available.

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Detection Guidance

To detect the CVE-2026-15619 vulnerability in mosaxiv clawlet, you can check for the presence of the affected versions (<= 0.2.10) and test for the SSRF vulnerability in the `web_fetch` tool.

• Verify the installed version of clawlet by running the command: `clawlet --version` or check the binary's version information. If the version is 0.2.10 or earlier, the system may be vulnerable.
• Test for the SSRF vulnerability by attempting to make a request to a non-public or special-use IPv4 address (e.g., 198.18.0.1) using the `web_fetch` tool. For example: `clawlet web_fetch http://198.18.0.1:18080/internal`. If the request succeeds, the system is vulnerable.
• Inspect the `tools/web_fetch_policy.go` file in the clawlet source code or configuration to check if the `allowHostByPolicy` function defaults to allowing all domains (`["*"]`) without IP-based restrictions. This is a key indicator of the vulnerability.
• Monitor network traffic for unexpected outbound HTTP/HTTPS requests to internal or non-public IP ranges, which may indicate exploitation of the SSRF vulnerability.

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Impact Analysis

If you are using mosaxiv clawlet versions 0.2.10 or earlier with the `web_fetch` tool enabled, this vulnerability could have several impacts:

• Internal Network Probing: An attacker could exploit the SSRF vulnerability to send requests to internal IP addresses, potentially discovering and interacting with services that are not meant to be publicly accessible. This could include databases, administrative interfaces, or other sensitive systems.
• Access to Local Services: The vulnerability could allow an attacker to access local services running on the same machine or network as the clawlet application. This might include services like local web servers, APIs, or other applications bound to localhost or private IP ranges.
• Cloud Metadata Endpoint Exposure: If the clawlet application is running in a cloud environment (e.g., AWS, Azure, GCP), an attacker could use the SSRF vulnerability to access cloud metadata endpoints. These endpoints often contain sensitive information such as credentials, API keys, or configuration details that could be used to escalate the attack further.
• Data Exfiltration: If internal services are accessible, an attacker could potentially exfiltrate sensitive data from those services, leading to a breach of confidentiality.
• Denial of Service: Repeated or malicious requests to internal services could cause those services to become unresponsive or crash, leading to a denial of service (DoS) condition.

The impact is particularly severe if the clawlet application is configured to allow user-influenced browsing behavior, as this could provide attackers with a direct way to manipulate the outbound requests.

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Compliance Impact

This vulnerability could have significant implications for compliance with various standards and regulations, depending on the context in which mosaxiv clawlet is used:

• GDPR (General Data Protection Regulation): If the SSRF vulnerability leads to unauthorized access to personal data stored in internal systems, this could constitute a data breach under GDPR. Organizations are required to implement appropriate technical and organizational measures to protect personal data. Failure to mitigate this vulnerability could result in non-compliance, leading to potential fines, legal action, or reputational damage.
• HIPAA (Health Insurance Portability and Accountability Act): For organizations handling protected health information (PHI), this vulnerability could lead to unauthorized access to PHI if internal healthcare systems are exposed. HIPAA requires strict controls over access to PHI, and an SSRF vulnerability that allows external attackers to probe or access internal systems could violate these requirements. Non-compliance with HIPAA can result in significant penalties and legal consequences.
• PCI DSS (Payment Card Industry Data Security Standard): If the clawlet application is used in an environment that processes, stores, or transmits payment card data, this vulnerability could expose internal systems handling such data. PCI DSS requires strict network segmentation and access controls to protect cardholder data. An SSRF vulnerability that allows access to internal payment systems could lead to non-compliance and potential fines or loss of payment processing capabilities.
• ISO 27001: This standard requires organizations to implement controls to manage information security risks. An SSRF vulnerability represents a failure to adequately protect against unauthorized access to internal systems, which could result in non-compliance with ISO 27001 requirements. Organizations may need to conduct a risk assessment and implement mitigations to address this vulnerability.

In summary, the vulnerability could lead to non-compliance with regulations and standards that mandate the protection of sensitive data and secure access to internal systems. Organizations should assess their exposure and take steps to mitigate the risk, such as updating the software, applying network-level protections, or disabling the vulnerable functionality.

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Mitigation Strategies

To mitigate CVE-2026-15619, follow these immediate steps:

• Upgrade clawlet to a version later than 0.2.10 if available. Since the GitHub issue was closed with the label 'not planned,' no official patch may exist, so consider alternative measures.
• Modify the `allowHostByPolicy` function in `tools/web_fetch_policy.go` to explicitly block special-use and non-global IPv4 ranges (e.g., 198.18.0.0/15, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16). Replace the default `["*"]` policy with a restrictive allowlist of trusted domains.
• Disable the `web_fetch` tool if it is not required for your use case. This can be done by removing or commenting out its configuration in the clawlet settings or restricting its access via filesystem permissions.
• Implement network-level controls, such as firewalls or security groups, to block outbound requests to internal or non-public IP ranges from the clawlet runtime environment.
• Monitor and log all outbound requests made by the `web_fetch` tool to detect and block suspicious activity. Use tools like Wireshark, tcpdump, or network monitoring solutions to track requests to unexpected destinations.
• Restrict user input that influences the `url` argument in the `web_fetch` function. Validate and sanitize all user-provided URLs to ensure they do not target internal or non-public resources.

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