CVE-2026-84857Public exploitNetwork attack vector

Unauthenticated service crash via unbounded request buffering

Published Sep 2, 2026 · Updated Sep 3, 2026

Uncontrolled memory allocation in Sigoden AIChat 0.30.0 through 0.30.4 allows remote attackers to crash its HTTP server. Four POST handlers in src/serve.rs collect each complete request body into memory before JSON parsing without enforcing a byte limit. Serve mode accepts these requests without API authentication, so one oversized body can exhaust process memory and interrupt model, embedding, rerank, and RAG APIs.

CVSS severityUnavailable
Unscored
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled memory allocation in Sigoden AIChat 0.30.0 through 0.30.4 allows remote attackers to crash its HTTP server. Four POST handlers in src/serve.rs collect each complete request body into memory before JSON parsing without enforcing a byte limit. Serve mode accepts these requests without API authentication, so one oversized body can exhaust process memory and interrupt model, embedding, rerank, and RAG APIs.

The record

CVE
CVE-2026-84857
Published
Sep 2, 2026
Updated
Sep 3, 2026
Vendor
Sigoden
Product
AIChat
Classifications
CWE-789, CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.30.0
  2. Affected versionversion=0.30.1
  3. Affected versionversion=0.30.2
  4. Affected versionversion=0.30.3
  5. Affected versionversion=0.30.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Sigoden · AIChatversion=0.30.0; version=0.30.1; version=0.30.2; version=0.30.3; version=0.30.4

Published CVSS scores

6.9VulDB CNACVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
5.3VulDB CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
5.0VulDB CNAAV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
5.3VulDB CNACVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Uncontrolled Memory Allocation
CWE-400Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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