EUVD-2026-74908
GHSA-wf68-h55h-fvxv
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-accessible unauthenticated deletion; no confidentiality impact; availability is high (recursive directory wipe); integrity rated low consistent with write-destructive rather than data-disclosure impact.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2DescriptionCVE.org
Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.
AnalysisAI
Unauthenticated remote directory deletion in Chainlit through 2.12.0 allows any network-accessible attacker to recursively destroy arbitrary filesystem directories reachable by the service process. The flaw resides in the socket.io session handler, which accepts a client-supplied sessionId without path sanitization and uses it directly in file system operations - permitting absolute and relative path traversal sequences to escape the intended upload directory. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | No special configuration is required beyond the Chainlit service being reachable over the network - the vulnerable code path is in the default socket.io session handling present in all Chainlit deployments through 2.12.0. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The provided CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N) reflects a genuinely dangerous profile: fully network-accessible, zero authentication, no complexity barrier, and high availability impact via recursive directory deletion. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch has been identified at time of analysis - the source code references provided point to the 2.12.0 codebase with no subsequent fix commit or tagged release indicated. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all Chainlit deployments running version 2.12.0 or earlier and restrict network access to socket.io endpoints via firewall rules, VPN-only access, or IP allowlisting to minimize exposure. …
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Unauthenticated remote code execution in Chainlit (2.4.0rc0 through 2.11.x) occurs when features.mcp.enabled is set to t
Server-side request forgery in Chainlit before 2.9.4 lets an authenticated user coerce the server into fetching an attac
Arbitrary file read in Chainlit versions prior to 2.9.4 lets an authenticated user disclose any file readable by the Cha
Session hijacking in Chainlit before 2.10.1 allows remote attackers with a valid victim sessionId to inherit an authenti
Feedback endpoint authorization bypass in Chainlit through 2.12.0 allows authenticated users to modify or delete other u
Same weakness CWE-22 – Path Traversal
View allSame technique Path Traversal
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External POC / Exploit Code
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