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.

CVSS v3 8.6 HIGH

8.6^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 4.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact HIGH

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-fc26-m9pf-v56q

Configurations

No configuration.

History

23 Oct 2026, 12:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-23 12:18

Updated : 2026-10-23 21:17

NVD link : CVE-2026-56837

Mitre link : CVE-2026-56837

CVE.ORG link : CVE-2026-56837

JSON object : View

Products Affected

No product.

CWE

CWE-287

Improper Authentication

CWE-306

Missing Authentication for Critical Function

CWE-347

Improper Verification of Cryptographic Signature

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