GoClaw EUVD-2026-43615

Exploitation requires the attacker to hold low-privilege authenticated credentials on the GoClaw instance, as confirmed by PR:L in the CVSS 4.0 vector - unauthenticated access is not sufficient. The target must be running GoClaw 3.13.3-beta.3 with the ACP ToolBridge Workspace Handler component active and network-accessible (AV:N). No user interaction is required (UI:N) and attack complexity is low (AC:L), meaning no race conditions or special timing is needed once authenticated. The key limiting factor is the authentication prerequisite: access must be obtained either through valid credentials, credential theft, or a preceding authentication bypass. The beta nature of the version may further limit the realistic deployment footprint in production environments.

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P) indicates a network-accessible, low-complexity attack with low-privilege authentication required and partial impact across confidentiality, integrity, and availability - no scope change to subsequent systems. The E:P supplement (exploit code published) is confirmed by the GitHub issue reference containing a publicly disclosed POC. The 5.3 base score accurately reflects limited direct impact: partial file read/write outside the workspace rather than full system compromise. EPSS data is not provided, and the absence of a KEV listing means active exploitation in the wild is unconfirmed. The primary real-world risk is chaining this traversal write primitive with other techniques - for example, writing to cron directories, SSH authorized_keys, or application config files - to escalate impact beyond what the low C/I/A scores suggest in isolation. The authentication requirement (PR:L) is the key limiting factor, reducing exposure compared to an unauthenticated variant.

An attacker with low-privilege authenticated access to a GoClaw deployment crafts a file write request to the ACP ToolBridge Workspace Handler, supplying a path such as ../../etc/cron.d/backdoor as the target for writeFile. The function does not canonicalize or restrict the path, allowing the write to land outside the workspace root. With a publicly available proof-of-concept on GitHub (https://github.com/nextlevelbuilder/goclaw/issues/1201), the attacker can adapt existing exploit code with minimal effort to achieve arbitrary file write on the server.