{"id":"PYSEC-2026-2562","summary":"LangChain affected by SSRF via image_url token counting in ChatOpenAI.get_num_tokens_from_messages","details":"## Server-Side Request Forgery (SSRF) in ChatOpenAI Image Token Counting\n\n### Summary\nThe `ChatOpenAI.get_num_tokens_from_messages()` method fetches arbitrary `image_url` values without validation when computing token counts for vision-enabled models. This allows attackers to trigger Server-Side Request Forgery (SSRF) attacks by providing malicious image URLs in user input.\n\n### Severity\n**Low** - The vulnerability allows SSRF attacks but has limited impact due to:\n- Responses are not returned to the attacker (blind SSRF)\n- Default 5-second timeout limits resource exhaustion\n- Non-image responses fail at PIL image parsing\n\n### Impact\nAn attacker who can control image URLs passed to `get_num_tokens_from_messages()` can:\n- Trigger HTTP requests from the application server to arbitrary internal or external URLs\n- Cause the server to access internal network resources (private IPs, cloud metadata endpoints)\n- Cause minor resource consumption through image downloads (bounded by timeout)\n\n**Note:** This vulnerability occurs during token counting, which may happen outside of model invocation (e.g., in logging, metrics, or token budgeting flows).\n\n### Details\nThe vulnerable code path:\n1. `get_num_tokens_from_messages()` processes messages containing `image_url` content blocks\n2. For images without `detail: \"low\"`, it calls `_url_to_size()` to fetch the image and compute token counts\n3. `_url_to_size()` performs `httpx.get(image_source)` on any URL without validation\n4. Prior to the patch, there was no SSRF protection, size limits, or explicit timeout\n\n**File:** `libs/partners/openai/langchain_openai/chat_models/base.py`\n\n### Patches\nThe vulnerability has been patched in `langchain-openai==1.1.9` (requires `langchain-core==1.2.11`).\n\nThe patch adds:\n1. **SSRF validation** using `langchain_core._security._ssrf_protection.validate_safe_url()` to block:\n   - Private IP ranges (RFC 1918, loopback, link-local)\n   - Cloud metadata endpoints (169.254.169.254, etc.)\n   - Invalid URL schemes\n2. **Explicit size limits** (50 MB maximum, matching OpenAI's payload limit)\n3. **Explicit timeout** (5 seconds, same as `httpx.get` default)\n4. **Allow disabling image fetching** via `allow_fetching_images=False` parameter\n\n### Workarounds\nIf you cannot upgrade immediately:\n\n1. **Sanitize input:** Validate and filter `image_url` values before passing messages to token counting or model invocation\n2. **Use network controls:** Implement egress filtering to prevent outbound requests to private IPs","aliases":["CVE-2026-26013","GHSA-2g6r-c272-w58r"],"modified":"2026-07-13T16:31:48.686407787Z","published":"2026-07-13T14:36:35.874621Z","references":[{"type":"WEB","url":"https://github.com/langchain-ai/langchain/security/advisories/GHSA-2g6r-c272-w58r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26013"},{"type":"WEB","url":"https://github.com/langchain-ai/langchain/commit/2b4b1dc29a833d4053deba4c2b77a3848c834565"},{"type":"PACKAGE","url":"https://github.com/langchain-ai/langchain"},{"type":"WEB","url":"https://github.com/langchain-ai/langchain/releases/tag/langchain-core%3D%3D1.2.11"},{"type":"PACKAGE","url":"https://pypi.org/project/langchain-core"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-2g6r-c272-w58r"}],"affected":[{"package":{"name":"langchain-core","ecosystem":"PyPI","purl":"pkg:pypi/langchain-core"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11"}]}],"versions":["0.0.1","0.0.10","0.0.11","0.0.12","0.0.13","0.0.13rc1","0.0.13rc2","0.0.2","0.0.3","0.0.4","0.0.5","0.0.6","0.0.7","0.0.8","0.0.9","0.1.0","0.1.1","0.1.10","0.1.11","0.1.12","0.1.12rc1","0.1.13","0.1.14","0.1.15","0.1.15rc1","0.1.15rc2","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","0.1.28","0.1.29","0.1.3","0.1.30","0.1.31","0.1.32","0.1.33","0.1.33rc1","0.1.34","0.1.35","0.1.36","0.1.37","0.1.38","0.1.39","0.1.4","0.1.40","0.1.41","0.1.42","0.1.42rc1","0.1.43","0.1.44","0.1.45","0.1.46","0.1.47","0.1.47rc1","0.1.48","0.1.49","0.1.5","0.1.50","0.1.51","0.1.52","0.1.53","0.1.6","0.1.7","0.1.8","0.1.9","0.2.0","0.2.0rc1","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.15","0.2.16","0.2.17","0.2.18","0.2.19","0.2.2","0.2.20","0.2.21","0.2.22","0.2.23","0.2.24","0.2.25","0.2.26","0.2.27","0.2.28","0.2.29","0.2.29rc1","0.2.2rc1","0.2.3","0.2.30","0.2.31","0.2.32","0.2.33","0.2.34","0.2.35","0.2.36","0.2.37","0.2.38","0.2.39","0.2.4","0.2.40","0.2.41","0.2.42","0.2.43","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.0.dev0","0.3.0.dev1","0.3.0.dev2","0.3.0.dev3","0.3.0.dev4","0.3.0.dev5","0.3.1","0.3.10","0.3.11","0.3.12","0.3.13","0.3.14","0.3.15","0.3.16","0.3.17","0.3.18","0.3.19","0.3.2","0.3.20","0.3.21","0.3.22","0.3.23","0.3.24","0.3.25","0.3.26","0.3.27","0.3.28","0.3.29","0.3.3","0.3.30","0.3.31","0.3.32","0.3.33","0.3.34","0.3.34rc1","0.3.34rc2","0.3.35","0.3.36","0.3.37","0.3.38","0.3.39","0.3.4","0.3.40","0.3.41","0.3.42","0.3.43","0.3.44","0.3.45","0.3.45rc1","0.3.46","0.3.47","0.3.48","0.3.49","0.3.5","0.3.50","0.3.51","0.3.52","0.3.53","0.3.54","0.3.55","0.3.56","0.3.56rc1","0.3.57","0.3.58","0.3.59","0.3.6","0.3.60","0.3.61","0.3.62","0.3.63","0.3.64","0.3.65","0.3.66","0.3.67","0.3.68","0.3.69","0.3.7","0.3.70","0.3.71","0.3.72","0.3.73","0.3.74","0.3.75","0.3.76","0.3.77","0.3.78","0.3.79","0.3.8","0.3.80","0.3.81","0.3.82","0.3.83","0.3.84","0.3.85","0.3.86","0.3.9","0.4.0.dev0","1.0.0","1.0.0a1","1.0.0a2","1.0.0a3","1.0.0a4","1.0.0a5","1.0.0a6","1.0.0a7","1.0.0a8","1.0.0rc1","1.0.0rc2","1.0.0rc3","1.0.1","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.1.0","1.1.1","1.1.2","1.1.3","1.2.0","1.2.1","1.2.10","1.2.2","1.2.3","1.2.4","1.2.5","1.2.6","1.2.7","1.2.8","1.2.9"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/langchain-core/PYSEC-2026-2562.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}