https://feed.craftedsignal.io/products/rclone/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioSat, 25 Apr 2026 12:00:00 +0000https://feed.craftedsignal.io/briefs/2026-04-rclone-rce/Sat, 25 Apr 2026 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2026-04-rclone-rce/Rclone versions prior to 1.73.5 are vulnerable to two critical unauthenticated remote code execution vulnerabilities (CVE-2026-41176 and CVE-2026-41179) when the remote control API is enabled without authentication, potentially allowing attackers to execute arbitrary commands and compromise the system.Two critical unauthenticated remote code execution vulnerabilities, CVE-2026-41176 and CVE-2026-41179, have been discovered in Rclone versions prior to 1.73.5. Rclone is a command-line program used to manage files on cloud storage services. These vulnerabilities can be exploited if the Rclone remote control (RC) API is enabled without proper authentication (e.g., --rc-user/--rc-pass/--rc-htpasswd). An attacker with network access to a vulnerable Rclone instance can bypass authentication, execute arbitrary commands, and potentially gain full system compromise. As organizations increasingly rely on cloud storage, vulnerabilities in tools like Rclone can have significant impact by enabling data theft and lateral movement. The vulnerabilities were reported on April 24, 2026, with no known active exploitation as of April 23, 2026.

Attack Chain

1. The attacker identifies a target system running Rclone with the RC API enabled.
2. The attacker verifies the RC API is exposed on a reachable network address (e.g., not only localhost) and is not protected by HTTP authentication.
3. For CVE-2026-41179, the attacker sends a single crafted HTTP request to the RC endpoint, leveraging the WebDAV backend initialization process.
4. This crafted request triggers the execution of arbitrary commands on the target system without authentication.
5. For CVE-2026-41176, the attacker bypasses authentication controls to access sensitive administrative functionality.
6. The attacker manipulates Rclone configuration or invokes operational RC methods to execute arbitrary commands.
7. The attacker gains local file read/write access, potentially stealing sensitive data or uploading malicious payloads.
8. The attacker achieves full system compromise, enabling data theft, lateral movement within the network, or denial of service.

Impact

Successful exploitation of CVE-2026-41176 and CVE-2026-41179 can lead to full system compromise, data theft, lateral movement, or denial of service. Specifically, attackers can achieve local file read, file write, or shell access, depending on the environment. The impact includes potential exposure of sensitive cloud data and configurations, which could compromise the integrity and confidentiality of stored information. Given Rclone’s popularity among organizations managing cloud storage, a successful attack could affect a large number of victims across various sectors.

Recommendation

• Upgrade Rclone to version 1.73.5 or later to patch CVE-2026-41176 and CVE-2026-41179 as recommended by the vendor.
• Enable global HTTP authentication on RC servers using --rc-user, --rc-pass, or --rc-htpasswd to mitigate the unauthenticated access, as mentioned in the description of the vulnerabilities.
• Implement network-level controls (e.g., firewall rules) to restrict access to RC server endpoints and the RC service, as suggested by CCB.
• Deploy the Sigma rule “Detect Rclone RC API Access Without Authentication” to identify potentially vulnerable Rclone instances within your environment.

]]>criticalthreatvulnerabilityrcecloudhttps://feed.craftedsignal.io/briefs/2026-04-rclone-auth-bypass/Thu, 23 Apr 2026 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2026-04-rclone-auth-bypass/Rclone is vulnerable to an unauthenticated options/set vulnerability that allows runtime authentication bypass, potentially leading to sensitive operations and command execution by setting `rc.NoAuth=true` on reachable RC servers started without global HTTP authentication.Rclone, a command-line program to manage files on cloud storage, is vulnerable to an authentication bypass via its remote control (RC) API. The vulnerability, present from version 1.45 onwards, stems from the options/set endpoint being exposed without authentication requirements, while still being able to modify the global runtime configuration. An unauthenticated attacker can exploit this vulnerability by setting the rc.NoAuth parameter to true, effectively disabling the authentication gate for numerous RC methods registered with AuthRequired: true. This allows unauthorized access to sensitive administrative functionality, including configuration settings and operational commands. The issue was validated against v1.73.4 and the current master branch as of April 14, 2026. This vulnerability is especially critical when the RC API is exposed without global HTTP authentication (i.e. --rc-user/--rc-pass are not set), as it allows complete control of the Rclone instance.

Attack Chain

1. An attacker identifies a vulnerable Rclone instance with the RC API enabled (via --rc or rclone rcd) that is reachable on the network. The attacker confirms that the RC API is not protected by global HTTP authentication (no --rc-user, --rc-pass, or --rc-htpasswd flags).
2. The attacker sends an unauthenticated POST request to the /options/set endpoint with a JSON payload setting rc.NoAuth to true: {"rc":{"NoAuth":true}}.
3. The Rclone RC server processes the request and updates the runtime configuration, disabling the authentication requirement for subsequent RC calls.
4. The attacker leverages the now-unprotected RC API to access sensitive configuration data using endpoints like /config/listremotes, /config/dump, or /config/get.
5. The attacker can list the available filesystems and remote configurations.
6. The attacker then uses operational endpoints such as /operations/list to list files and directories within a configured remote.
7. The attacker exploits the /operations/copyfile endpoint to copy files from one location to another, potentially exfiltrating sensitive data or overwriting critical files.
8. Finally, the attacker uses the /core/command endpoint to execute arbitrary commands on the host system, achieving complete system compromise. This endpoint utilizes the exec.Command(...) function, allowing arbitrary command execution.

Impact

Successful exploitation of this vulnerability allows an unauthenticated attacker to bypass intended access controls on the Rclone RC administrative interface. The impact ranges from sensitive configuration disclosure and filesystem enumeration to arbitrary command execution on the host system. This could lead to complete system compromise, data exfiltration, or denial of service. The vulnerability affects Rclone instances from version 1.45 up to (but not including) 1.73.5. The severity is amplified when the RC API is exposed to a wider network without proper authentication measures.

Recommendation

• Upgrade Rclone to version 1.73.5 or later to patch CVE-2026-41176.
• If upgrading is not immediately feasible, ensure that the Rclone RC API is protected by global HTTP authentication using the --rc-user, --rc-pass, or --rc-htpasswd flags.
• Monitor network traffic for POST requests to the /options/set endpoint without authentication, indicative of exploitation attempts. Deploy the provided Sigma rule to detect this activity.
• Review Rclone RC API access logs for unauthorized access to sensitive endpoints such as /config/listremotes, /config/dump, /config/get, /operations/list, /operations/copyfile, and /core/command after the /options/set endpoint has been accessed.

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