Langflow up to 1.6.9 Refresh Endpoint origin validation

Summaryinfo

A vulnerability was found in Langflow up to 1.6.9. It has been classified as critical. This vulnerability affects unknown code of the component Refresh Endpoint. The manipulation leads to origin validation. This vulnerability is referenced as CVE-2025-34291. Remote exploitation of the attack is possible. Furthermore, an exploit is available.

Detailsinfo

A vulnerability was found in Langflow up to 1.6.9 and classified as critical. This issue affects an unknown code block of the component Refresh Endpoint. The manipulation with an unknown input leads to a origin validation vulnerability. Using CWE to declare the problem leads to CWE-346. The product does not properly verify that the source of data or communication is valid. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Langflow versions up to and including 1.6.9 contain a chained vulnerability that enables account takeover and remote code execution. An overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) combined with a refresh token cookie configured as SameSite=None allows a malicious webpage to perform cross-origin requests that include credentials and successfully call the refresh endpoint. An attacker-controlled origin can therefore obtain fresh access_token / refresh_token pairs for a victim session. Obtained tokens permit access to authenticated endpoints — including built-in code-execution functionality — allowing the attacker to execute arbitrary code and achieve full system compromise.

The weakness was published by Fenix Qiao. It is possible to read the advisory at obsidiansecurity.com. The identification of this vulnerability is CVE-2025-34291 since 04/15/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are unknown but an exploit is available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/21/2026).

It is declared as attacked. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 05/21/2026 with a due date of 06/04/2026:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-201507). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

• Langflow

Version

• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3
• 1.6.4
• 1.6.5
• 1.6.6
• 1.6.7
• 1.6.8
• 1.6.9

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion