CVEs / CVE-2026-55255
CVE-2026-55255: Langflow Authorization Bypass Through User-Controlled Key Vulnerability
- Known exploited in the CISA KEV catalog since 7 Jul 2026
- high 8.4 CVSS 3.1 (from the CNA)
- EPSS 0.88% chance of exploitation in the next 30 days, higher than 59% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Langflow contains an authorization bypass through user-controlled key vulnerability which allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.
Description
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| langflow-ai langflow | < 1.9.1 | — |
| Product | Affected | Fixed in |
|---|---|---|
| langflow (PyPI) | before 1.9.1 | 1.9.1 |
Package versions from GHSA-qrpv-q767-xqq2.
Exploitation
| In CISA KEV since | 7 Jul 2026 |
|---|---|
| Due date for US federal agencies | 10 Jul 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. |
Severity
| CVSS 3.1 | 8.4 highCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:LScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-639 |
References
- CVE-2026-55255 on NVD
- CVE-2026-55255 in the CISA KEV catalog
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- CVE-2026-55255 on OSV
- https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e Patch
- https://github.com/langflow-ai/langflow/pull/12832 Issue Tracking, Patch
- https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2 Exploit, Mitigation, Vendor Advisory
- https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.