CVE-2026-84857
Received Received - Intake

Uncontrolled Memory Allocation in Aichat API Endpoint

Publication date: 2026-09-02

Last updated on: 2026-09-02

Assigner: VulDB

Description
A flaw has been found in sigoden aichat up to 0.30.4. This affects an unknown function of the file src/serve.rs of the component API Endpoint. This manipulation causes uncontrolled memory allocation. The attack can be initiated remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

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Meta Information

Published
2026-09-02
Last Modified
2026-09-02
Generated
2026-09-03
AI Q&A
2026-09-02
EPSS Evaluated
N/A
NVD
CVE-2026-84857

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
sigoden aichat to 0.30.4 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-789 The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.

Attack-Flow Graph

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Executive Summary

CVE-2026-84857 is a denial of service vulnerability in AIChat version 0.30.0 affecting HTTP serve request body handling. The issue occurs in OpenAI-compatible HTTP serve mode, specifically in routes like /v1/chat/completions and /v1/embeddings. These routes collect the entire HTTP request body into memory before processing without enforcing limits on request size, JSON depth, or string length.

Detection Guidance

Monitor for unusually large HTTP request bodies being sent to the affected endpoints (/v1/chat/completions, /v1/embeddings, /v1/rerank, /v1/rags/search). Use network traffic analysis tools like tcpdump or Wireshark to inspect request sizes. Check server logs for crashes or high memory usage during API requests.

Impact Analysis

An unauthenticated attacker can exploit this by sending an oversized request body, causing the service to allocate excessive memory and potentially crash. This makes normal API requests unavailable, disrupting service functionality for all users.

Compliance Impact

This vulnerability may impact compliance with GDPR and HIPAA by enabling denial of service attacks that disrupt service availability. GDPR requires data processing systems to ensure availability and resilience, while HIPAA mandates safeguards against unauthorized access or disruptions. Uncontrolled memory allocation could lead to service outages, potentially violating these requirements.

Mitigation Strategies

Implement a hard HTTP request body byte limit before buffering. Add API authentication or restrict serve mode to local-only access. Replace full-body buffering with bounded streaming reads. Set rate and concurrent request limits. Avoid logging complete request bodies.

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