CVE-2026-8319Public exploitNetwork attack vector

Unauthenticated worker crash via unbounded tokenization

Published May 11, 2026 · Updated May 11, 2026

Resource exhaustion in Cheshire Cat AI core allows remote attackers to crash backend workers through an oversized /message request. The recall_relevant_memories_to_working_memory function sends unbounded message text to tiktoken.encode, whose Rust parser panics on stack overflow and terminates the FastAPI worker. No authentication or user interaction is required; repeated requests can keep containerized instances unavailable without reported data exposure or modification.

CVSS severity7.5
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Cheshire Cat AI core allows remote attackers to crash backend workers through an oversized /message request. The recall_relevant_memories_to_working_memory function sends unbounded message text to tiktoken.encode, whose Rust parser panics on stack overflow and terminates the FastAPI worker. No authentication or user interaction is required; repeated requests can keep containerized instances unavailable without reported data exposure or modification.

The record

CVE
CVE-2026-8319
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Cheshire Cat AI
Product
core
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=e8c4e3c2d19739d3dff59e577d1c97090cc15f59

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cheshire Cat AI · coreversion=e8c4e3c2d19739d3dff59e577d1c97090cc15f59

Published CVSS scores

5.5GitHub Advisory DatabaseCVSS: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
7.5GitHub issue 219CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-400Uncontrolled Resource 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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