CVE-2026-92576 Overview
CVE-2026-92576 is a Server-Side Request Forgery (SSRF) vulnerability in HKUDS nanobot versions prior to 0.3.0. The flaw resides in the WebFetchTool component, where the _validate_url() function fails to block internal IP ranges and private addresses. Attackers can instruct the bot to fetch cloud metadata endpoints, localhost services, and RFC 1918 addresses. Successful exploitation exposes Identity and Access Management (IAM) credentials and internal service data. The vulnerability is tracked under CWE-918 and is triggerable remotely without authentication or user interaction.
Critical Impact
Unauthenticated attackers can pivot through the bot to reach cloud instance metadata services and extract IAM credentials, enabling broader compromise of cloud infrastructure.
Affected Products
- HKUDS nanobot versions before 0.3.0
- Deployments using the WebFetchTool component
- Cloud-hosted nanobot instances with access to metadata endpoints
Discovery Timeline
- 2026-09-16 - CVE-2026-92576 published to the National Vulnerability Database (NVD)
- 2026-09-17 - Last updated in NVD database
Technical Details for CVE-2026-92576
Vulnerability Analysis
The vulnerability originates in the _validate_url() function within the WebFetchTool component of HKUDS nanobot. The function is intended to restrict outbound requests to safe destinations but does not enforce checks against private or internal address ranges. As a result, any URL a user submits to the bot is fetched by the server-side process without adequate destination filtering.
Attackers exploit this by sending crafted messages that direct the bot to internal addresses. Targets include cloud provider metadata services such as http://169.254.169.254/latest/meta-data/, localhost services bound to loopback interfaces, and RFC 1918 ranges like 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Fetched responses are returned through the bot interface, leaking sensitive contents including IAM session tokens.
Root Cause
The root cause is incomplete URL validation logic. _validate_url() does not resolve hostnames to their underlying IP addresses and does not maintain a denylist for link-local, loopback, and private ranges. DNS-based bypasses and direct IP targeting both succeed against the validator.
Attack Vector
Exploitation requires only network access to the nanobot messaging interface. An attacker sends a message containing a URL pointing at an internal resource. The WebFetchTool component issues the request from the server context and returns response data to the attacker. No credentials, elevated privileges, or user interaction are required.
For implementation-level details, refer to the GitHub Security Advisory GHSA-vc5v-6vwm-wf9m and the VulnCheck Advisory for HKUDS Nanobot.
Detection Methods for CVE-2026-92576
Indicators of Compromise
- Outbound HTTP requests from nanobot processes to 169.254.169.254, metadata.google.internal, or 100.100.100.200
- Bot-originated connections to loopback (127.0.0.0/8) or RFC 1918 addresses
- Unusual response payloads in bot conversation logs containing tokens, JSON credentials, or internal hostnames
- Unexpected IAM credential usage from workload identities associated with nanobot deployments
Detection Strategies
- Inspect nanobot application logs for WebFetchTool invocations targeting non-public IP addresses or metadata hostnames
- Correlate egress network flows from bot infrastructure with allow-listed external destinations
- Alert on cloud audit logs showing IAM credentials being used from IP addresses that differ from the assigned workload identity
Monitoring Recommendations
- Enable cloud provider Instance Metadata Service Version 2 (IMDSv2) or equivalent session-based metadata protections
- Log and retain all URLs fetched by the bot for forensic review
- Monitor for anomalous DNS queries resolving public hostnames to private IP addresses
How to Mitigate CVE-2026-92576
Immediate Actions Required
- Upgrade HKUDS nanobot to version 0.3.0 or later
- Rotate any IAM credentials and API tokens accessible from the nanobot host or workload identity
- Audit conversation and application logs for prior WebFetchTool calls targeting internal addresses
- Restrict egress network policy on nanobot hosts to only required external destinations
Patch Information
The fix is available in HKUDS nanobot version 0.3.0. Upgrade guidance and patch notes are published in the GitHub Security Advisory GHSA-vc5v-6vwm-wf9m.
Workarounds
- Deploy an egress proxy that denies requests to link-local, loopback, and RFC 1918 destinations
- Enforce IMDSv2 on AWS instances to require session tokens for metadata access
- Run nanobot in a network namespace that removes routes to internal management networks
- Disable or remove the WebFetchTool component if URL fetching is not required
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
