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Fencer Vulns
high 8.6

CVE-2026-56837 json

PraisonAI LinearBot processes unsigned webhooks when LINEAR_WEBHOOK_SECRET is missing

published 2026-06-18 4 mo ago modified 2026-10-23 16 d ago also EUVD-2026-108878 , GHSA-fc26-m9pf-v56q , PYSEC-2026-3510

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi praisonai 4.6.59
  • praison praisonai 4.6.59

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
16 d ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
OSV 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Affected packages

ecosystem package affected fixed in
pypi praisonai
>=4.6.56, <4.6.59
4.6.59

Affected products

  • MervinPraison PraisonAI

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.