CVE-2026-55531 PraisonAI MCP HTTP server has unauthenticated unbounded session accumulation (memory exhaustion; session TTL never enforced)
Unauthenticated attackers can exhaust memory by creating unlimited sessions in the PraisonAI MCP HTTP server, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55531?
CVE-2026-55531 is a medium-severity denial of service vulnerability in MervinPraison PraisonAI, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, the MCP HTTP Stream mcp_post handler creates a new _sessions entry for every initialize request but does not call _cleanup_sessions or enforce a maximum. An unauthenticated caller can exhaust memory. The fix invokes cleanup and limits sessions through PRAISONAI_MCP_MAX_SESSIONS. This issue is fixed in version 4.6.58.
Which versions are affected by CVE-2026-55531?
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-2026-55531?
Upgrade praisonai to 4.6.58 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-55531 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55531 exists.
Sources
Also known as GHSA-wv94-5qcp-6m36, PYSEC-2026-3897.