CVE-2026-56837

PraisonAI is a multi-agent teams system. From version 4.6.56 to before version 4.6.59, PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely. An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token. The PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary. This issue has been patched in version 4.6.59.

PraisonAI is a multi-agent teams system. From version 4.6.56 to before version 4.6.59, PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely. An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token. The PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary. This issue has been patched in version 4.6.59.

PraisonAI LinearBot processes unsigned webhooks when LINEAR_WEBHOOK_SECRET is missing

Summary

PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely.

An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token.

The local PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary:

• no secret configured: unsigned forged webhook returns 200, invokes the agent session path once, and attempts one Linear comment;
• secret configured: missing and bad signatures both return 401 and do not invoke the agent;
• secret configured with valid HMAC: request returns 200 and invokes the agent, proving the control path still works.

Affected Product

• Repository: MervinPraison/PraisonAI
• Package: praisonai
• Components:
  • src/praisonai/praisonai/bots/linear.py
  • src/praisonai/praisonai/cli/features/bots_cli.py

Validated affected:

• live main / latest observed release v4.6.58: 1ad58ca02975ff1398efeda694ea2ab78f20cf3e
• previous local current checkout: 2f9677abb2ea68eab864ee8b6a828fd0141612e1
• v4.6.57
• v4.6.56
• v4.5.50

Sampled tags where the LinearBot component was not present:

• v4.5.49
• v4.5.51
• v4.6.9
• v4.6.10

Suggested affected range: LinearBot-bearing releases with the fail-open signature behavior, at least 4.5.50 and >= 4.6.56, <= 4.6.58. The component appears non-contiguously in sampled tags, so maintainers should confirm the exact packaged version history before publishing a final range.

Root Cause

LinearBot.__init__() accepts an empty signing secret and falls back to an empty environment value:

self._signing_secret = signing_secret or os.environ.get("LINEAR_WEBHOOK_SECRET", "")

start() treats the missing secret as a warning instead of refusing to expose the webhook listener:

if not self._signing_secret:
    logger.warning("LINEAR_WEBHOOK_SECRET not set - webhook signatures will not be verified")

self._site = web.TCPSite(self._runner, "0.0.0.0", self._webhook_port)

_handle_webhook() only verifies the request if the secret is truthy:

if self._signing_secret:
    signature = request.headers.get("Linear-Signature", "")
    if not self._verify_signature(raw_body, signature):
        return web.Response(status=401, text="Invalid signature")

With no secret configured, the code continues to JSON parsing, accepts a caller supplied webhookTimestamp, reads the caller supplied Linear-Event header, and schedules processing:

event_type = request.headers.get("Linear-Event", "")
task = asyncio.create_task(self._process_webhook(event_type, body))
return web.Response(status=200, text="OK")

For AgentSession, the forged body is routed to the agent:

if event_type == "AgentSession":
    await self._handle_agent_session(body)
...
response = await self._session_mgr.chat(self._agent, user_id, message.content)
await self._send_comment(...)

The CLI has the same fail-open posture: start_linear() loads LINEAR_WEBHOOK_SECRET, prints a warning when it is missing, then reports a public http://0.0.0.0:<port>/webhook endpoint with verification disabled.

Why This Is Not Intended Behavior

PraisonAI's Linear Bot documentation tells operators to set LINEAR_WEBHOOK_SECRET, pass it to praisonai bot linear, copy the Linear webhook signing secret, and use it for…

PraisonAI is a multi-agent teams system. From version 4.6.56 to before version 4.6.59, PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely. An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token. The PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary. This issue has been patched in version 4.6.59.

PraisonAI is a multi-agent teams system. From version 4.6.56 to before version 4.6.59, PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely. An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token. The PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary. This issue has been patched in version 4.6.59.

PraisonAI LinearBot processes unsigned webhooks when LINEAR_WEBHOOK_SECRET is missing

Summary

PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely.

An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token.

The local PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary:

• no secret configured: unsigned forged webhook returns 200, invokes the agent session path once, and attempts one Linear comment;
• secret configured: missing and bad signatures both return 401 and do not invoke the agent;
• secret configured with valid HMAC: request returns 200 and invokes the agent, proving the control path still works.

Affected Product

• Repository: MervinPraison/PraisonAI
• Package: praisonai
• Components:
  • src/praisonai/praisonai/bots/linear.py
  • src/praisonai/praisonai/cli/features/bots_cli.py

Validated affected:

• live main / latest observed release v4.6.58: 1ad58ca02975ff1398efeda694ea2ab78f20cf3e
• previous local current checkout: 2f9677abb2ea68eab864ee8b6a828fd0141612e1
• v4.6.57
• v4.6.56
• v4.5.50

Sampled tags where the LinearBot component was not present:

• v4.5.49
• v4.5.51
• v4.6.9
• v4.6.10

Suggested affected range: LinearBot-bearing releases with the fail-open signature behavior, at least 4.5.50 and >= 4.6.56, <= 4.6.58. The component appears non-contiguously in sampled tags, so maintainers should confirm the exact packaged version history before publishing a final range.

Root Cause

LinearBot.__init__() accepts an empty signing secret and falls back to an empty environment value:

self._signing_secret = signing_secret or os.environ.get("LINEAR_WEBHOOK_SECRET", "")

start() treats the missing secret as a warning instead of refusing to expose the webhook listener:

if not self._signing_secret:
    logger.warning("LINEAR_WEBHOOK_SECRET not set - webhook signatures will not be verified")

self._site = web.TCPSite(self._runner, "0.0.0.0", self._webhook_port)

_handle_webhook() only verifies the request if the secret is truthy:

if self._signing_secret:
    signature = request.headers.get("Linear-Signature", "")
    if not self._verify_signature(raw_body, signature):
        return web.Response(status=401, text="Invalid signature")

With no secret configured, the code continues to JSON parsing, accepts a caller supplied webhookTimestamp, reads the caller supplied Linear-Event header, and schedules processing:

event_type = request.headers.get("Linear-Event", "")
task = asyncio.create_task(self._process_webhook(event_type, body))
return web.Response(status=200, text="OK")

For AgentSession, the forged body is routed to the agent:

if event_type == "AgentSession":
    await self._handle_agent_session(body)
...
response = await self._session_mgr.chat(self._agent, user_id, message.content)
await self._send_comment(...)

The CLI has the same fail-open posture: start_linear() loads LINEAR_WEBHOOK_SECRET, prints a warning when it is missing, then reports a public http://0.0.0.0:<port>/webhook endpoint with verification disabled.

Why This Is Not Intended Behavior

PraisonAI's Linear Bot documentation tells operators to set LINEAR_WEBHOOK_SECRET, pass it to praisonai bot linear, copy the Linear webhook signing secret, and use it for…

PraisonAI LinearBot processes unsigned webhooks when LINEAR_WEBHOOK_SECRET is missing

Summary

PraisonAI's LinearBot starts a public webhook listener on 0.0.0.0 and treats LINEAR_WEBHOOK_SECRET as optional. When the secret is absent, startup only logs a warning and _handle_webhook() skips Linear-Signature verification entirely.

An unauthenticated network caller who can reach the webhook endpoint can submit a forged Linear-Event: AgentSession request. The forged request is parsed, scheduled for background processing, dispatched to _handle_agent_session(), and passed into BotSessionManager.chat(). The bot then attempts to post the agent response back to Linear under the configured bot token.

The local PoV is offline and deterministic. It does not contact Linear. It calls the webhook handler directly, monkey-patches the outbound Linear comment path, and proves both sides of the boundary:

• no secret configured: unsigned forged webhook returns 200, invokes the agent session path once, and attempts one Linear comment;
• secret configured: missing and bad signatures both return 401 and do not invoke the agent;
• secret configured with valid HMAC: request returns 200 and invokes the agent, proving the control path still works.

Affected Product

• Repository: MervinPraison/PraisonAI
• Package: praisonai
• Components:
  • src/praisonai/praisonai/bots/linear.py
  • src/praisonai/praisonai/cli/features/bots_cli.py

Validated affected:

• live main / latest observed release v4.6.58: 1ad58ca02975ff1398efeda694ea2ab78f20cf3e
• previous local current checkout: 2f9677abb2ea68eab864ee8b6a828fd0141612e1
• v4.6.57
• v4.6.56
• v4.5.50

Sampled tags where the LinearBot component was not present:

• v4.5.49
• v4.5.51
• v4.6.9
• v4.6.10

Suggested affected range: LinearBot-bearing releases with the fail-open signature behavior, at least 4.5.50 and >= 4.6.56, <= 4.6.58. The component appears non-contiguously in sampled tags, so maintainers should confirm the exact packaged version history before publishing a final range.

Root Cause

LinearBot.__init__() accepts an empty signing secret and falls back to an empty environment value:

self._signing_secret = signing_secret or os.environ.get("LINEAR_WEBHOOK_SECRET", "")

start() treats the missing secret as a warning instead of refusing to expose the webhook listener:

if not self._signing_secret:
    logger.warning("LINEAR_WEBHOOK_SECRET not set - webhook signatures will not be verified")

self._site = web.TCPSite(self._runner, "0.0.0.0", self._webhook_port)

_handle_webhook() only verifies the request if the secret is truthy:

if self._signing_secret:
    signature = request.headers.get("Linear-Signature", "")
    if not self._verify_signature(raw_body, signature):
        return web.Response(status=401, text="Invalid signature")

With no secret configured, the code continues to JSON parsing, accepts a caller supplied webhookTimestamp, reads the caller supplied Linear-Event header, and schedules processing:

event_type = request.headers.get("Linear-Event", "")
task = asyncio.create_task(self._process_webhook(event_type, body))
return web.Response(status=200, text="OK")

For AgentSession, the forged body is routed to the agent:

if event_type == "AgentSession":
    await self._handle_agent_session(body)
...
response = await self._session_mgr.chat(self._agent, user_id, message.content)
await self._send_comment(...)

The CLI has the same fail-open posture: start_linear() loads LINEAR_WEBHOOK_SECRET, prints a warning when it is missing, then reports a public http://0.0.0.0:<port>/webhook endpoint with verification disabled.

Why This Is Not Intended Behavior

PraisonAI's Linear Bot documentation tells operators to set LINEAR_WEBHOOK_SECRET, pass it to praisonai bot linear, copy the Linear webhook signing secret, and use it for…