High Info disclosure

CVE-2026-39889 — PraisonAI has Unauthenticated SSE Event Stream Exposes All Agent Activity in A2U Server

PraisonAI is a multi-agent teams system. Prior to 4.5.115, the A2U (Agent-to-User) event stream server in PraisonAI exposes all agent activity without authentication. The create_a2u_routes() function registers the following endpoints with NO authentication checks: /a2u/info, /a2u/subscribe, /a2u/events/{stream_name}, /a2u/events/sub/{id}, and /a2u/health. This vulnerability is fixed in 4.5.115.

Published Apr 8, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.5% (30-day exploitation probability)+6
Technical severity (high)+6
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.48%

ahead of 40% of scored CVEs · Oct 14, 2026

Affects

MervinPraison

PraisonAI and 1 more

CVSS base

7.5

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (MervinPraison PraisonAI, Praison Praisonai).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (info disclosure), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
MervinPraison	PraisonAI	version < 4.5.115	Vulnerable	CVE Program (cve.org) e CISA ADP
Praison	Praisonai	≤ 4.5.114	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	security-advisories@github.com via NIST National Vulnerability Database
7.5	CVSS 3.1	High	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-200 · Exposure of Sensitive Information

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.48%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Look for anomalous data read/export volumes and access to sensitive records.

web/proxy/WAF logsnetwork IDS/IPSapplication logsauthentication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · mervinpraison/praisonai
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 7.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Apr 8, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmf
Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

MervinPraison
every CVE for this vendor

Info disclosure
same class

CWE-200
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-57118 PraisonAI AgentTeam.launch exposes unauthenticated remote agent listing and invocation endpoints 3d
Critical CVE-2026-62176 PraisonAI: Code Injection via f-string Interpolation in Deploy API Server Generation 8d
Critical CVE-2026-61447 PraisonAI before 1.6.78 Remote Code Execution via CodeAgent Jul 11, 2026
Critical CVE-2026-61445 PraisonAI before 4.6.78 Arbitrary File Write and Command Execution Jul 11, 2026
High CVE-2026-61442 PraisonAI Platform before 0.1.9 Authorization Bypass via PATCH Jul 11, 2026
Critical CVE-2026-60090 PraisonAI before 4.6.78 SQL/CQL Injection via vector dimension Jul 11, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-39889 is "PraisonAI has Unauthenticated SSE Event Stream Exposes All Agent Activity in A2U Server", rated High. It affects PraisonAI (MervinPraison); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.48% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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