CVE-2026-15625 Overview
CVE-2026-15625 affects nextlevelbuilder GoClaw version 3.11.3. The vulnerability resides in the ExecApprovalManager.CheckCommand function within internal/tools/exec_approval.go. An incomplete blacklist [CWE-183] in the command approval logic allows attackers to bypass command filtering controls remotely. The flaw impacts confidentiality, integrity, and availability at a limited scope. A public proof-of-concept exists, increasing the likelihood of opportunistic exploitation attempts against exposed instances.
Critical Impact
Remote attackers with low privileges can bypass command approval filters through inputs not covered by the incomplete blacklist, enabling execution of restricted commands.
Affected Products
- nextlevelbuilder GoClaw 3.11.3
- Component: internal/tools/exec_approval.go
- Function: ExecApprovalManager.CheckCommand
Discovery Timeline
- 2026-07-14 - CVE-2026-15625 published to NVD
- 2026-07-14 - Last updated in NVD database
Technical Details for CVE-2026-15625
Vulnerability Analysis
The vulnerability originates in the command approval subsystem of GoClaw. The ExecApprovalManager.CheckCommand function evaluates commands against a denylist before permitting execution. Because the blacklist enumerates only known-bad strings, it fails to account for variant syntaxes, alternate encodings, or semantically equivalent commands.
Attackers can craft inputs that produce the intended dangerous behavior while evading the blacklist match. This class of weakness is tracked as [CWE-183] Permissive List of Allowed Inputs, where reliance on denylists rather than allowlists produces predictable bypass conditions.
The attack is executable over the network and requires only low privileges. No user interaction is needed. A public proof-of-concept has been referenced in GitHub Issue #1200 on the upstream repository.
Root Cause
The root cause is design-level reliance on an incomplete denylist to enforce command approval. Blacklists cannot enumerate every dangerous input, and any command outside the enumerated set is permitted by default. The correct pattern is an explicit allowlist of approved commands with canonical normalization prior to comparison.
Attack Vector
An authenticated remote attacker submits a command through the GoClaw execution approval interface. The submitted command is constructed to be functionally equivalent to a restricted operation but syntactically outside the blacklist. CheckCommand returns an approval decision, and the command proceeds to execution.
No verified exploit code is available for reproduction here. See GitHub Issue #1200 and the VulDB entry for CVE-2026-15625 for technical details.
Detection Methods for CVE-2026-15625
Indicators of Compromise
- Approved command execution events in GoClaw logs where the command string contains unusual encoding, whitespace padding, or shell metacharacter substitutions.
- Repeated CheckCommand invocations from a single low-privileged principal probing variant syntaxes.
- Execution of shell utilities or interpreters that would normally be denied by policy.
Detection Strategies
- Enable verbose logging on ExecApprovalManager.CheckCommand decisions to capture the exact command string evaluated.
- Correlate approval decisions with downstream process execution telemetry to identify commands permitted despite policy intent.
- Deploy anomaly detection on the frequency and diversity of commands submitted per user account.
Monitoring Recommendations
- Alert on any successful command approval containing shell operators, backticks, or subshell syntax.
- Monitor authentication events preceding command submission for credential stuffing or brute-force patterns.
- Forward GoClaw application logs to a centralized SIEM for retention and cross-source correlation.
How to Mitigate CVE-2026-15625
Immediate Actions Required
- Restrict network access to GoClaw instances to trusted administrative networks only.
- Reduce the number of accounts with command submission privileges to the minimum required.
- Audit historical CheckCommand decisions for evidence of blacklist bypass attempts.
Patch Information
No fixed version has been published in the enriched data at the time of writing. Track the upstream repository at nextlevelbuilder/goclaw and GitHub Issue #1200 for remediation progress. Apply any vendor-issued patch as soon as it becomes available.
Workarounds
- Replace the denylist-based approval logic with an explicit allowlist of approved commands where source modification is feasible.
- Add a network-layer proxy or WAF rule to reject requests to the approval endpoint containing shell metacharacters.
- Require secondary out-of-band approval for any command execution request originating from non-privileged accounts.
# Configuration example
# Restrict access to the GoClaw approval endpoint at the network layer
iptables -A INPUT -p tcp --dport <goclaw-port> -s <admin-cidr> -j ACCEPT
iptables -A INPUT -p tcp --dport <goclaw-port> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
