LangChain is a framework for building agents and LLM-powered applications. Prior to 1.1.14, langchain-openai's _url_to_size() helper (used by get_num_tokens_from_messages for image token counting) validated URLs for SSRF protection and then fetched them in a separate network operation with independent DNS resolution. This left a TOCTOU / DNS rebinding window: an attacker-controlled hostname could resolve to a public IP during validation and then to a private/localhost IP during the actual fetch.

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Fri, 24 Apr 2026 21:15:00 +0000

Type Values Removed Values Added
Description LangChain is a framework for building agents and LLM-powered applications. Prior to 1.1.14, langchain-openai's _url_to_size() helper (used by get_num_tokens_from_messages for image token counting) validated URLs for SSRF protection and then fetched them in a separate network operation with independent DNS resolution. This left a TOCTOU / DNS rebinding window: an attacker-controlled hostname could resolve to a public IP during validation and then to a private/localhost IP during the actual fetch.
Title angchain-openai: Image token counting SSRF protection can be bypassed via DNS rebinding
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 3.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-24T20:57:25.658Z

Reserved: 2026-04-20T16:14:19.007Z

Link: CVE-2026-41488

cve-icon Vulnrichment

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cve-icon NVD

Status : Received

Published: 2026-04-24T21:16:19.637

Modified: 2026-04-24T21:16:19.637

Link: CVE-2026-41488

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses