CVE-2026-56837 PraisonAI LinearBot processes unsigned webhooks when LINEAR_WEBHOOK_SECRET is missing
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-56837?
CVE-2026-56837 is a high-severity vulnerability in MervinPraison PraisonAI, published on 23 Oct 2026.
Official description
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.
Which versions are affected by CVE-2026-56837?
3 open source packages ship an affected version, including praisonai.
| Package | Affected | Fixed in |
|---|---|---|
praisonai PyPI | From 4.6.56 | 4.6.59 |
praisonai PyPI | From 4.6.56 | 4.6.59 |
praisonai PyPI | From 4.6.56 | 4.6.59 |
How do I fix CVE-2026-56837?
Upgrade praisonai to 4.6.59 or later.
Is CVE-2026-56837 being exploited?
There is no known exploitation of CVE-2026-56837 in the wild and no public exploit code.
Sources
Also known as GHSA-fc26-m9pf-v56q, PYSEC-2026-3510.