CVE-2026-8447Network attack vectorHinoki check available

Session theft via unsanitized raw HTML rendering

Published Sep 4, 2026 · Updated Sep 4, 2026

Stored XSS in IBM Langflow OSS 1.0.0 through 1.11.2 allows remote attackers to steal session tokens via crafted chat output. The Playground's MarkdownField component passes attacker-controlled LLM response text through rehypeRaw without sanitization, inserting raw HTML into the browser DOM. Exploitation requires a user to view the poisoned conversation; a superuser victim's session can expose the flow-build code-execution path.

CVSS severity6.1
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in IBM Langflow OSS 1.0.0 through 1.11.2 allows remote attackers to steal session tokens via crafted chat output. The Playground's MarkdownField component passes attacker-controlled LLM response text through rehypeRaw without sanitization, inserting raw HTML into the browser DOM. Exploitation requires a user to view the poisoned conversation; a superuser victim's session can expose the flow-build code-execution path.

The record

CVE
CVE-2026-8447
Published
Sep 4, 2026
Updated
Sep 4, 2026
Vendor
IBM
Product
Langflow OSS
Classifications
CWE-79, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 4, 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=1.0.0 <=1.11.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · Langflow OSSversion=1.0.0 <=1.11.2

Published CVSS scores

6.1IBMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1539Steal Web Session Cookie

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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