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 328 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)
- 92.8% probability of exploitation in the next 30 days, higher than 99.8% 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 2026-10-08
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. Weaponised exploit code for CVE-2025-34291 is publicly available. 3 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (http/cves/2025/CVE-2025-34291.yaml). It currently carries a trending score of 50 in the Threadlinqs vulnerability feed.
- amnnrth/CVE-2025-34291_cors_security_scanner (github)
- ridhinva/langflow-cors-scanner (github)
- trickest/cve (trickest)
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.
Sources
Enriched from CVE.org, FIRST EPSS, CISA KEV, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on .