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Exploitation reportedNot in CISA KEV yetFix available

CVE-2026-55450

Exploitation reported by one source. First attested on 2026-08-09 by GCVE · kevintel.

  • Published2026-06-23
  • Fixed in1.9.1
  • WeaknessCWE-200 · CWE-306 · CWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-06-2317:17CVE publishedNVD
  2. 2026-08-0912:09Listed as exploited by GCVEGCVE
  3. 2026-08-0912:09Exploitation first reportedGCVE
  4. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-55450?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-55450?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Langflow
BranchAffectedFixed in
1.9< 1.9.11.9.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Langflow to 1.9.1

Advisories and patches

Detection

read 2026-10-23 19:25 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverified0xBlackash/CVE-2026-55450
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • GCVEexploitation2026-08-09
  • CISA-ADPSSVC decisionpoc2026-06-23
  • OpenCVESSVC decisionpoc—
  • CNACVSS 3.19.3read 2026-10-23
  • CNAweakness (CWE)CWE-200, CWE-306, CWE-400read 2026-10-23
  • FIRST EPSSEPSS score1.2 %2026-10-22
  • PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H
Published
2026-06-23
Last Modified
2026-06-24
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-55450?

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.

Is CVE-2026-55450 actively exploited?

A proof-of-concept exploit exists for CVE-2026-55450, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-55450?

CVE-2026-55450 has a CVSS v3 base score of 9.3 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H.

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