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)
Attackers can bypass WebSocket origin validation to execute unauthorized browser automation commands in PraisonAI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55536?
CVE-2026-55536 is a critical vulnerability in MervinPraison PraisonAI, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server _handle_connection() 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 start_session commands and unauthorized browser automation. This issue is fixed in version 4.6.58.
Which versions are affected by CVE-2026-55536?
3 open source packages ship an affected version, including praisonai and PraisonAI.
| Package | Affected | Fixed in |
|---|---|---|
praisonai PyPI | All versions | 4.6.58 |
praisonai PyPI | All versions | 4.6.58 |
PraisonAI PyPI | All versions | 4.6.58 |
How do I fix CVE-2026-55536?
Upgrade praisonai to 4.6.58 or later.
Is CVE-2026-55536 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55536 exists.
Sources
Also known as GHSA-6g6r-q6gw-w8fg, PYSEC-2026-3886.