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Actively exploitedCVSS 8.8 · HIGH

CVE-2025-34291

Langflow contains an origin validation error vulnerability in which an overly permissive CORS configuration 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. This could allow the attacker to execute arbitrary code and achieve full system compromise via obtained tokens that permit access to authenticated endpoints.

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Severity

Score: 8.8(HIGH)
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AV: NETWORK
AC: LOW
PR: LOW
UI: NONE
S: UNCHANGED
C: HIGH
I: HIGH
A: HIGH
Weakness (CWE): CWE-346

CISA KEV

Added to KEV: 2026-05-21
Federal patch deadline: 2026-06-04
Known ransomware use: Unknown
Required action

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

EPSS

Probability of exploitation (next 30 days): 0.3185 (31.9%)
Percentile: 96.9%
EPSS: 2026-05-25

Affects

langflow:langflow

Technical description

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.

Published: 12/5/2025, 11:15:47 PM
Last modified: 5/21/2026, 8:16:13 PM

References

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