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CVE-2026-40289

9.1
Critical
EPSS 0.36%Patch availableApr 14, 2026

Unauthenticated session hijack via PraisonAI WebSocket /ws

common questions

Is CVE-2026-40289 being exploited?

Not confirmed. CVE-2026-40289 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.36% probability of exploitation in the next 30 days.

How severe is CVE-2026-40289?

CVE-2026-40289 is rated Critical with a CVSS score of 9.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-40289?

Yes. A fix has been recorded for CVE-2026-40289. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-40289 affect?

CVE-2026-40289 affects PraisonAI < 4.5.139, praisonaiagents < 1.5.140. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-40289?

Upgrade to 4.5.139 / 1.5.140

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
PraisonAI < 4.5.139praisonaiagents < 1.5.140
impact

Unauthenticated remote hijack of browser automation sessions; attacker can access page context and results and misuse actions.

action required

Patch when possible

affected versions
MervinPraison PraisonAI
  • affected< 4.5.139
MervinPraison praisonaiagents
  • affected< 1.5.140

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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