## Langchain-OpenAI Security Flaw: SSRF & DNS Rebinding Risk in AI Image Token Counter
A critical security vulnerability in the popular Langchain-OpenAI library exposes AI applications to server-side request forgery (SSRF) and DNS rebinding attacks. The flaw, tracked as GHSA-r7w7-9xr2-qq2r, resides in the `_url_to_size()` helper function, a core component used for counting image tokens in AI message processing. This function's flawed design creates a dangerous time-of-check to time-of-use (TOCTOU) window, allowing attackers to bypass security validations and force the application to fetch malicious content from internal network resources.

The vulnerability specifically affects the `get_num_tokens_from_messages` method. The function first validates a user-supplied URL for SSRF protection but then performs a separate, independent network fetch and DNS resolution. This gap between validation and execution is the attack surface. An attacker can initially provide a benign, validated URL, but during the DNS rebinding window, they can switch the domain's IP address to point to internal, sensitive services—like cloud metadata endpoints, internal APIs, or databases—that the application server can reach but an external attacker normally cannot.

This is not a theoretical risk. The Langchain-OpenAI library is a foundational dependency for countless AI agents, chatbots, and automation pipelines that process multimedia content. The flaw could allow data exfiltration from internal networks, lateral movement, or service disruption. The maintainers have released patched versions (v1.1.14 and later) to close this window. All projects using `langchain-openai` must immediately update from vulnerable versions like 1.1.12. The incident underscores the complex security challenges in AI dependency chains, where a single helper function in a widely adopted library can become a systemic risk point for the entire ecosystem.
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- **Source**: GitHub Issues
- **Sector**: The Lab
- **Tags**: AI Security, Supply Chain, SSRF, DNS Rebinding, Vulnerability
- **Credibility**: unverified
- **Published**: 2026-04-20 13:22:58
- **ID**: 72524
- **URL**: https://whisperx.ai/en/intel/72524