Chainlit contains a session hijacking vulnerability

Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the...

PYSEC-2026-3812 Chainlit has command injection via MCP stdio transport that allows unauthenticated remote code execution

Am I affected? Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. Summary When MCP ...

Chainlist has SSRF via MCP SSE and streamable-http transports that allows unauthenticated internal network access

Am I affected?Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. SummaryWhen MCP is...

PYSEC-2026-3811 Chainlist has SSRF via MCP SSE and streamable-http transports that allows unauthenticated internal network access

Am I affected? Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. Summary When MCP ...

Chainlit has command injection via MCP stdio transport that allows unauthenticated remote code execution

Am I affected?Only if your deployment sets features.mcp.enabled = true in .chainlit/config.toml. MCP has been disabled by default since v2.7.0, so most Chainlit deployments are not affected. No authentication is required: /mcp is reachable by any client that can open a session. SummaryWhen MCP is...

agentengine-sdk-python (>=0.2.0, <=0.4.0), agentic-chat-ui (>=0.1.0, <=0.2.4) +46 more potentially affected by CVE-2026-86099 via chainlit (>=1.0.0, <=2.12.0)

chainlit PYPI version =1.0.0, =0.2.0, =0.1.0, =0.3.0, =0.0.3, =0.14.0, =0.0.0, =0.1.1, =0.1.1, =0.1.0, =0.1.0, =0.1.0, =1.0.0, =0.0.2, =0.1.0 - context-protector 1.0.0 and more Source cves: CVE-2026-86099 Source advisory: SNYK:PYTHON-CHAINLIT-19659988...

Directory Traversal

Overview chainlit is a Build Conversational AI. Affected versions of this package are vulnerable to Directory Traversal via the client-supplied sessionId handling in backend/chainlit/session.py and backend/chainlit/socket.py. An attacker can delete arbitrary directories accessible to the service...

CVE-2026-86099

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...

CVE-2026-86099 Chainlit through 2.12.0 Path Traversal via socket.io sessionId

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...

CVE-2026-86099

Chainlit versions through 2.12.0 fail to validate the client-supplied socket.io sessionId parameter, enabling unauthenticated attackers to perform path traversal by injecting absolute or relative path sequences. Maliciously crafted sessionId values can escape the upload directory and recursively ...

EUVD-2026-74908

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...

CVE-2026-86099 Chainlit through 2.12.0 Path Traversal via socket.io sessionId

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...

CVE-2026-86099 Chainlit through 2.12.0 Path Traversal via socket.io sessionId

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...

CVE-2026-86099: Improper Limitation of a Pathname to a Restricted Directory

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...

PT-2026-89000

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...

Authorization Bypass Through User-Controlled Key

Overview chainlit is a Build Conversational AI. Affected versions of this package are vulnerable to Authorization Bypass Through User-Controlled Key in the feedback PUT and DELETE endpoints in backend/chainlit/server.py. An authenticated attacker can modify or delete other users’ feedback by...

CVE-2026-82290

Chainlit through 2.12.0 fails to validate ownership of feedback records in PUT and DELETE endpoints. Authenticated attackers can delete or modify other users' feedback by supplying arbitrary feedback identifiers, corrupting human-rating data used for model evaluation...

CVE-2026-82290 Chainlit Feedback Endpoints Missing Ownership Validation

Chainlit through 2.12.0 fails to validate ownership of feedback records in PUT and DELETE endpoints. Authenticated attackers can delete or modify other users' feedback by supplying arbitrary feedback identifiers, corrupting human-rating data used for model evaluation...

CVE-2026-82290 Chainlit Feedback Endpoints Missing Ownership Validation

Chainlit through 2.12.0 fails to validate ownership of feedback records in PUT and DELETE endpoints. Authenticated attackers can delete or modify other users' feedback by supplying arbitrary feedback identifiers, corrupting human-rating data used for model evaluation...

CVE-2026-82290

Chainlit through version 2.12.0 fails to validate ownership of feedback records in its PUT and DELETE endpoints. The root cause is a missing ownership check, allowing authenticated attackers to delete or modify other users' feedback by supplying arbitrary feedback identifiers. The practical conse...