Summary
langchain-openai: Image token counting SSRF protection can be bypassed via DNS rebinding
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.
The practical impact is limited because the fetched response body is passed directly to Pillow's Image.open() to extract dimensions, the response content is never returned, logged, or otherwise exposed to the caller. An attacker cannot exfiltrate data from internal services through this path. A potential risk is blind probing (inferring whether an internal host/port is open based on timing or error behavior).
Affected versions
langchain-openai< 1.1.14
Patched versions
langchain-openai>= 1.1.14 (requireslangchain-core>= 1.2.31)
Affected code
File: libs/partners/openai/langchain_openai/chat_models/base.py, _url_to_size()
The vulnerable pattern was a validate-then-fetch with separate DNS resolution:
validate_safe_url(image_source, allow_private=False, allow_http=True)
# ... separate network operation with independent DNS resolution ...
response = httpx.get(image_source, timeout=timeout)
Impact
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
CVE-2026-41488 has a CVSS score of 3.1 (Low). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.1.14); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The fix replaces the validate-then-fetch pattern with an SSRF-safe httpx transport (SSRFSafeSyncTransport from langchain-core) that:
- Resolves DNS once and validates all returned IPs against a policy (private ranges, cloud metadata, localhost, k8s internal DNS)
- Pins the connection to the validated IP, eliminating the DNS rebinding window
- Disables redirect following to prevent redirect-based SSRF bypasses
This fix was released in langchain-openai 1.1.14.
Frequently Asked Questions
- What is CVE-2026-41488? CVE-2026-41488 is a low-severity server-side request forgery (SSRF) vulnerability in langchain-openai (pip), affecting versions < 1.1.14. It is fixed in 1.1.14. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
- How severe is CVE-2026-41488? CVE-2026-41488 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of langchain-openai are affected by CVE-2026-41488? langchain-openai (pip) versions < 1.1.14 is affected.
- Is there a fix for CVE-2026-41488? Yes. CVE-2026-41488 is fixed in 1.1.14. Upgrade to this version or later.
- Is CVE-2026-41488 exploitable, and should I be worried? Whether CVE-2026-41488 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-41488 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-41488? Upgrade
langchain-openaito 1.1.14 or later.