---
title: "CVE-2026-55536: PraisonAI has a Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)"
url: https://erroneo.us/security/cve/CVE-2026-55536/
description: "CVE-2026-55536 (PraisonAI (PyPI)): PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server handleconnection() checks Chrome…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-25
date_modified: 2026-08-28
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-55536"
kev: false
cvss: 9.1
epss: 0.00521
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-55536: PraisonAI has a Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 43: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 43% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes PraisonAI (PyPI) < 4.6.58, fixed in 4.6.58 . Check your lockfile, including transitive dependencies.

## What it is

PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server handleconnection() checks Chrome extension origins with re.match() and the unanchored expression chrome-extension://[a-z0-9]{32}. Extra trailing characters pass before websocket.accept(), allowing startsession commands and unauthorized browser automation. This issue is fixed in version 4.6.58.

## Affected packages

- PyPI `PraisonAI` < 4.6.58 → fixed: 4.6.58

## Affected products (CVE record)

- MervinPraison PraisonAI: < 4.6.58

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.52% probability of exploitation activity in the next 30 days; percentile 43.

## Sources

- [GitHub Advisory GHSA-6g6r-q6gw-w8fg](https://github.com/advisories/GHSA-6g6r-q6gw-w8fg)
- [CVE.org record CVE-2026-55536](https://www.cve.org/CVERecord?id=CVE-2026-55536)
- [NVD entry CVE-2026-55536](https://nvd.nist.gov/vuln/detail/CVE-2026-55536)
- [github.com](https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-6g6r-q6gw-w8fg)
- [github.com](https://github.com/MervinPraison/PraisonAI/commit/2f9677abb2ea68eab864ee8b6a828fd0141612e1)
- [github.com](https://github.com/MervinPraison/PraisonAI/releases/tag/v4.6.58)

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Source page: https://erroneo.us/security/cve/CVE-2026-55536/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt