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CVE-2026-56837

HIGH 8.6

Published 2026-10-23 · Last modified 2026-10-23

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.

ELEVATED IMPACT

Severe if exploited (CVSS 8.6), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 8th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

8.6CVSS 3.1 · HIGH

  • ConfidentialityLow
  • IntegrityHigh
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

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Data snapshot:

Affected

Vendors Mervinpraison

Products Praisonai

Weakness (CWE)

  • CWE-287: : Improper Authentication
  • CWE-306: : Missing Authentication for Critical Function
  • CWE-347: : Improper Verification of Cryptographic Signature

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

References and research data (JSON)

Packages and version ranges

Each advisory describes its own package and affected ranges. A boundary applies to that range; it is not a universal upgrade recommendation.

  • praisonai PyPI

    pkg:pypi/praisonai

    ECOSYSTEM range
    • Introduced version (included): 4.6.56
    • Fixed boundary (excluded): 4.6.59
    3 explicitly listed affected versions

    4.6.56, 4.6.57, 4.6.58

    Additional upstream package constraints
    {
  "database": {
    "last_known_affected_version_range": "<= 4.6.58",
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-fc26-m9pf-v56q/GHSA-fc26-m9pf-v56q.json"
  }
}
    GitHub Advisory Database · GHSA-fc26-m9pf-v56q · Updated 2026-07-23T15:11:39.851493687Z
  • praisonai PyPI

    pkg:pypi/praisonai

    ECOSYSTEM range
    • Introduced version (included): 4.6.56
    • Fixed boundary (excluded): 4.6.59
    3 explicitly listed affected versions

    4.6.56, 4.6.57, 4.6.58

    Additional upstream package constraints
    {
  "database": {
    "source": "https://github.com/pypa/advisory-database/blob/main/vulns/praisonai/PYSEC-2026-3510.yaml"
  }
}
    PyPA · PYSEC-2026-3510 · Updated 2026-07-23T15:00:20.789202469Z

All CVSS metrics

  • HIGH 8.6 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
  • HIGH 8.6 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS