Flowise: Pyodide validator Unicode homoglyph bypass leads to RCE
FlowiseAI · Flowise
Official source article: GitHub GHSA-52FH-8V99-63C2 ↗. Check the applicable product and release in the original source.
9.5CriticalCVSS 4.0
Recommended action
Within 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-52811
No EUVD known-exploited evidence
ENISA has published the identifier mapping but no EUVD description has been stored yet.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
Patch available
01
What, why and how
Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise validatePythonCodeForDataFrame in packages/components/src/pythonCodeValidator.ts can be bypassed with Unicode homoglyph identifiers, allowing arbitrary Python execution inside Pyodide and full OS command execution on the Flowise host via Pyodide js module interop. The validator gates pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts with an ASCII word-boundary blacklist. JavaScript regex word boundaries are ASCII-only, while Python 3 NFKC-normalizes identifiers at parse time, so homoglyph forms such as __cl𝐚ss__, __subcl𝐚sses__, __b𝐚se__, and __b𝐮iltins__ bypass the blacklist and are parsed as their ASCII equivalents. This issue is fixed in version 3.1.3.
What
Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise validatePythonCodeForDataFrame in packages/components/src/pythonCodeValidator.ts can be bypassed with Unicode homoglyph identifiers, allowing arbitrary Python execution inside Pyodide and full OS command execution on the Flowise host via Pyodide js module interop. The validator gates pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts with an ASCII word-boundary blacklist. JavaScript regex word boundaries are ASCII-only, while Python 3 NFKC-normalizes identifiers at parse time, so homoglyph forms such as __cl𝐚ss__, __subcl𝐚sses__, __b𝐚se__, and __b𝐮iltins__ bypass the blacklist and are parsed as their ASCII equivalents. This issue is fixed in version 3.1.3.
Why
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise validatePythonCodeForDataFrame in packages/components/src/pythonCodeValidator.ts can be bypassed with Unicode homoglyph identifiers, allowing arbitrary Python execution inside Pyodide and full OS command execution on the Flowise host via Pyodide js module interop. The validator gates pyodide.runPythonAsync in packages/components/nodes/agents/CSVAgent/CSVAgent.ts and packages/components/nodes/agents/AirtableAgent/AirtableAgent.ts with an ASCII word-boundary blacklist. JavaScript regex word boundaries are ASCII-only, while Python 3 NFKC-normalizes identifiers at parse time, so homoglyph forms such as __cl𝐚ss__, __subcl𝐚sses__, __b𝐚se__, and __b𝐮iltins__ bypass the blacklist and are parsed as their ASCII equivalents. This issue is fixed in version 3.1.3.
Why
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
a network path → Incomplete List of Disallowed Inputs → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Not a CVSS 4.0 base metric
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-184: Incomplete List of Disallowed Inputs. The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCHighSubsequent-system confidentiality: A successful attack can cause a major loss.SIHighSubsequent-system integrity: A successful attack can cause a major loss.SAHighSubsequent-system availability: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Ein Angreifer kann mehrere Schwachstellen in Flowise ausnutzen, um beliebigen Code auszuführen – sogar mit Root-Rechten –, erweiterte Privilegien zu erlangen, Sicherheitsmaßnahmen zu umgehen, Sitzungen zu kapern sowie Daten offenzulegen oder zu manipulieren.
Official advisory ↗Cyber Security Agency of Singapore · English · CSA-SB-20260805Security Bulletin 5 Aug 2026
The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 5 Aug 2026, published on 5 August 2026. Open the linked bulletin for the product, severity and reference information published in that issue.
Official advisory ↗CSIRT Italia · Italian · aggiornamenti-di-sicurezza-per-flowiseAggiornamenti di sicurezza per Flowise
Sono stati recentemente resi pubblici diversi Proof of Concept (PoC) relativi a vulnerabilità che interessano la piattaforma Flowise riportati di seguito:
CVE-2026-70476: la vulnerabilità potrebbe consentire la manipolazione non autorizzata di informazioni associate ai processi di billing e gestione delle risorse applicative. Un eventuale sfruttamento potrebbe compromettere l'integrità dei dati, alterare processi amministrativi e generare modifiche non autorizzate ai meccanismi di contabilizzazione delle risorse.
CVE-2026-70474: la vulnerabilità interessa i meccanismi di autenticazione e autorizzazione basati su OAuth. Un attaccante potrebbe ottenere accessi non autorizzati a risorse e funzionalità applicative, con potenziale compromissione della riservatezza dei dati e delle identità digitali associate alla piattaforma.
CVE-2026-70473: la vulnerabilità potrebbe consentire l'accesso non autorizzato a funzionalità e informazioni che dovrebbero risultare protette. Lo sfruttamento potrebbe permettere l'elusione di controlli applicativi e l'accesso non autorizzato a dati sensibili.
CVE-2026-70470: la vulnerabilità potrebbe consentire l'esecuzione di operazioni non previste sui componenti vulnerabili della piattaforma. Un eventuale sfruttamento potrebbe compromettere l'integrità dell'ambiente applicativo e favorire attività ostili successive.
CVE-2026-69264: la vulnerabilità interessa il componente CSVAgent e può consentire l'esecuzione di codice remoto attraverso l'iniezione di contenuto controllato dall'attaccante in codice Python eseguito tramite Pyodide. Un attaccante potrebbe eseguire comandi di sistema, accedere a file locali e compromettere completamente l'istanza vulnerabile.
CVE-2026-69263: la vulnerabilità potrebbe consentire l’elusione di una precedente mitigazione relativa all'esecuzione di pacchetti tramite npx. Lo sfruttamento potrebbe permettere l'installazione e l'esecuzione non autorizzata di codice con i privilegi del processo Flowise, con conseguente compromissione del sistema.
CVE-2026-69257: la vulnerabilità potrebbe consentire il bypass delle protezioni SSRF tramite indirizzi IPv4-mapped IPv6. Un attaccante potrebbe raggiungere servizi interni, endpoint cloud metadata o risorse normalmente non accessibili, con potenziale esposizione di credenziali, token e informazioni sensibili.
CVE-2026-69256: la vulnerabilità interessa il nodo CSVAgent e consente l'esecuzione di codice arbitrario sfruttando la funzione pandas.read_pickle() per aggirare i controlli di sicurezza implementati. L'impatto può tradursi nella completa compromissione dell'istanza Flowise e nell'esecuzione di comandi arbitrari.
CVE-2026-69255: la vulnerabilità potrebbe consentire l'esecuzione di codice arbitrario tramite iniezione di codice Python nel componente CSVAgent. Le evidenze pubblicate riportano l'ottenimento di una shell con privilegi elevati all'interno del container Flowise, con possibilità di accesso ai dati, esecuzione di comandi arbitrari e movimenti laterali verso ulteriori sistemi raggiungibili dall'host compromesso.
Official advisory ↗JVN iPedia · Japanese · JVNDB-2026-033556flowiseaiのflowiseにおける不完全なブラックリストに関する脆弱性
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 4 Aug 2026 · Last source change 4 Aug 2026, 19:51 UTC · CWE-184 · Incomplete List of Disallowed Inputs
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-52811
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.