CVE-2025-34291 — Langflow
CISA KEVRansomwareAs of 2026-05-22, CVE-2025-34291 is a HIGH-severity vulnerability in Langflow, CVSS v3.1 8.8, EPSS 35.3% (97.1th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-21), with a US federal remediation deadline of 2026-06-04, and CISA links it to known ransomware campaigns. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2025-34291, most recently “CISA KEV (2026-05-21): CVE-2025-34291 Langflow CORS Token Hijack-to-RCE & CVE-2026-34926 Trend Micro Apex One On-Premise Directory Traversal”.
Last updated: 2026-05-22
What is CVE-2025-34291?
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 record classifies CVE-2025-34291 under weakness class CWE-346. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 282 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 8.8 — HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS v4.0 base score
- 9.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - EPSS (FIRST)
- 35.3% probability of exploitation in the next 30 days, higher than 97.1% of all scored CVEs
- CISA KEV
- Listed since 2026-05-21, federal remediation deadline 2026-06-04 — used in known ransomware campaigns
- Threadlinqs priority
- 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- Published
- 2025-12-05, last modified 2026-05-22
Is CVE-2025-34291 being exploited?
CISA added CVE-2025-34291 to the Known Exploited Vulnerabilities catalog on 2026-05-21, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-06-04 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.
Affected products and versions
- Langflow: Langflow
How to fix CVE-2025-34291
Because CVE-2025-34291 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-06-04. No vendor patch reference has been recorded for CVE-2025-34291 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2025-34291
1 tracked threat in the Threadlinqs corpus references CVE-2025-34291, either in the campaign’s CVE list or as an indicator on the campaign record.
- CISA KEV (2026-05-21): CVE-2025-34291 Langflow CORS Token Hijack-to-RCE & CVE-2026-34926 Trend Micro Apex One On-Premise Directory Traversal — CRITICAL · 2026-05-21
Sources
Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.
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