CVE-2026-56676: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in decolua 9router
9Router is an AI router & token saver. Prior to 0.5.2, 9router validates image URLs by resolving the host before fetching, but open-sse/translator/concerns/image.js performs the later server-side image fetch with a separate DNS resolution. An authenticated attacker with access to the LLM proxy can use a vision-capable model and an attacker-controlled DNS name that first resolves to a public IP and then rebinds to an internal address, allowing server-side requests to internal-only HTTP services. This issue is fixed in version 0.5.2.
AI Analysis
Technical Summary
9router versions before 0.5.2 contain a TOCTOU race condition in the image URL validation and fetching process. The host is resolved during validation, but the actual fetch uses a separate DNS resolution, enabling an attacker controlling DNS to rebind the address between these steps. This can be exploited by an authenticated attacker with LLM proxy access to cause server-side requests to internal HTTP services, potentially exposing internal resources. The vulnerability is addressed in version 0.5.2.
Potential Impact
An authenticated attacker with access to the LLM proxy can leverage this vulnerability to perform server-side request forgery (SSRF) against internal-only HTTP services by exploiting the DNS rebinding race condition. This can lead to information disclosure and potentially impact confidentiality, integrity, and availability of internal services as indicated by the CVSS vector (C:L/I:L/A:L).
Mitigation Recommendations
Upgrade to decolua 9router version 0.5.2 or later, where this TOCTOU race condition vulnerability is fixed. No other mitigation guidance is provided, and patch status is not explicitly stated but the fix version is known.
CVE-2026-56676: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition in decolua 9router
Description
9Router is an AI router & token saver. Prior to 0.5.2, 9router validates image URLs by resolving the host before fetching, but open-sse/translator/concerns/image.js performs the later server-side image fetch with a separate DNS resolution. An authenticated attacker with access to the LLM proxy can use a vision-capable model and an attacker-controlled DNS name that first resolves to a public IP and then rebinds to an internal address, allowing server-side requests to internal-only HTTP services. This issue is fixed in version 0.5.2.
CVSS v3.1
Score 7.4high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
9router versions before 0.5.2 contain a TOCTOU race condition in the image URL validation and fetching process. The host is resolved during validation, but the actual fetch uses a separate DNS resolution, enabling an attacker controlling DNS to rebind the address between these steps. This can be exploited by an authenticated attacker with LLM proxy access to cause server-side requests to internal HTTP services, potentially exposing internal resources. The vulnerability is addressed in version 0.5.2.
Potential Impact
An authenticated attacker with access to the LLM proxy can leverage this vulnerability to perform server-side request forgery (SSRF) against internal-only HTTP services by exploiting the DNS rebinding race condition. This can lead to information disclosure and potentially impact confidentiality, integrity, and availability of internal services as indicated by the CVSS vector (C:L/I:L/A:L).
Mitigation Recommendations
Upgrade to decolua 9router version 0.5.2 or later, where this TOCTOU race condition vulnerability is fixed. No other mitigation guidance is provided, and patch status is not explicitly stated but the fix version is known.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-22T16:39:01.044Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a51144968715ace43c8e2aa
Added to database: 07/10/2026, 15:48:25 UTC
Last enriched: 07/18/2026, 15:30:03 UTC
Last updated: 08/24/2026, 10:52:10 UTC
Views: 83
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