Cline Kanban Server has a Cross-Origin WebSocket Hijacking Vulnerability

published 2026-05-08 6 mo ago modified 2026-07-22 3 mo ago also EUVD-2026-33662 , GHSA-5c57-rqjx-35g2

cvss: 9.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits: 0; none known

Cline is an autonomous coding agent as an SDK, IDE extension, or CLI assistant. In versions 2.13.0 and prior, there is a cross-origin WebSocket hijack vulnerability in Cline Kanban servers. At time of publication, there are no publicly available patches.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 5 mo ago (2026-06-03)

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/cline/cline/security/advisories/GHSA-5c57-rqjx-35g2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
GitHub	3.1	9.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	cline	<=2.13.0	no fix listed

Affected products

cline cline

Classification

Weakness

CWE-306 Missing Authentication for Critical Functionality
CWE-1385 Missing Origin Validation in WebSockets

References

github.com /cline/cline/security/advisories/GHSA-5c57-rqjx-35g2
exploit, web, mitigation, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-44211
advisory
github.com /cline/cline
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary