What it is
CVE-2026-55450 is an unauthenticated vulnerability affecting langflow-ai langflow. Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, unauthenticated users can upload any...
Vulnerability report
Active exploitation observed
Confirmed confidence
Not in CISA KEV
CVE-2026-55450
langflow Denial of Service
langflow-ai / langflow · affected before 1.9.1
- Severity
- CVSS 9.3 · Critical
- Confidence
- Confirmed
- Exploit status
- Observed in sensors
- EPSS
- 11.8%
- First observed
- 08 Aug 2026
- Last observed
- 09 Aug 2026
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEVIntel sensors observed exploitation attempts with confirmed confidence.
Who is affected?
langflow-ai / langflow affected before 1.9.1.
What should we do?
Patch immediately, validate internet-facing exposure, and monitor for matching requests.
Overview
Langflow is a tool for building and deploying AI-powered agents and workflows
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow.
This can lead to space exhaustion on the server. In addition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. This vulnerability is fixed in 1.9.1.
Vendor
Product
Affected
Status
langflow-ai
langflow
Before 1.9.1
Affected
- Published
- 23 Jun 2026
- Exploitation Reported
- 08 Aug 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
CVE References
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735 github.com · CVE Record https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223...
- https://github.com/langflow-ai/langflow/pull/12831 github.com · CVE Record https://github.com/langflow-ai/langflow/pull/12831
Exploitation evidence
Why KEVIntel marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
KEVIntel
Independent exploitation attestation added to the KEVIntel record.
Active exploitation observed
KEVIntel sensor
First-party sensor telemetry confirms matching exploitation attempts.
Proof of concept available
Nuclei Templates
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| KEVIntel First | 2026-08-09 12:09 UTC |
Operational indicators for this CVE are listed under Detection.
Sensor telemetry
First-party evidence of exploitation activity
Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.
2
Attempts observed
2
Unique attacker IPs
2
Attacker countries
FR · US
1
Sensors observed
Exploitation attempts over the last 7 days
Daily events observed by KEVIntel sensors
Updated 09 Aug 2026
Aug
3
Aug
4
Aug
5
Aug
6
Aug
7
Aug
8
Aug
9
First observed 08 Aug 2026 · Last observed 09 Aug 2026
Pro adds sensor region and window summaries. Enterprise adds raw IPs, paths, User-Agents, and payloads.
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 1
- User-Agents
- 2
Raw values available in Pro and Enterprise.
Scanner coverage
Nuclei template detected 01 Aug 2026.
View Nuclei template (opens in new tab)Virtual patch status
No KEVIntel virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Attacker IP Indicators
Attacker IP indicators observed · available in Pro and Enterprise.
Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.
Learn about Pro API accessScanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-55450.yaml | 01 Aug 2026 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
9.3
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H
EPSS
11.8%
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
Langflow < 1.9.1 - Unauthenticated File Upload
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
Observed by KEVIntel sensors
Evidence-backed exploitation signal
-
Indicators of compromise added (2)
Indicators of compromise recorded
-
Public PoC available
Public proof-of-concept code published
-
Nuclei template available
Scanner coverage available
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2026-55450
Free JSON includes basic KEV fields{
"cve_id": "CVE-2026-55450",
"confidence": "Confirmed",
"cvss_score": 9.3,
"epss_score": 0.11819,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": true
},
"sensor_telemetry": { "attempts": 2, "sensors": 1 }
}