How severe is CVE-2026-39890?

CVE-2026-39890 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-39890 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39890?

CVE-2026-39890 affects Praison Praisonai. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39890?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-39890 have an EU (EUVD) identifier?

Yes. CVE-2026-39890 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20638.

When was CVE-2026-39890 published?

CVE-2026-39890 was published on 2026-04-08 and last updated on 2026-07-24.

CVE-2026-39890

CVE-2026-39890 is a critical-severity vulnerability in Praison Praisonai with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20638
Weakness: CWE-502
Affected product: Praison Praisonai
Published: 2026-04-08
Last modified: 2026-07-24

Description

PraisonAI is a multi-agent teams system. Prior to 4.5.115, the AgentService.loadAgentFromFile method uses the js-yaml library to parse YAML files without disabling dangerous tags (such as !!js/function and !!js/undefined). This allows an attacker to craft a malicious YAML file that, when parsed, executes arbitrary JavaScript code. An attacker can exploit this vulnerability by uploading a malicious agent definition file via the API endpoint, leading to remote code execution (RCE) on the server. This vulnerability is fixed in 4.5.115.

Frequently asked questions

What is CVE-2026-39890?: PraisonAI is a multi-agent teams system. Prior to 4.5.115, the AgentService.loadAgentFromFile method uses the js-yaml library to parse YAML files without disabling dangerous tags (such as !!js/function and !!js/undefined). This allows an attacker to craft a malicious YAML file that, when parsed, executes arbitrary JavaScript code. An attacker can exploit this vulnerability by uploading a malicious agent definition file via the API endpoint, leading to remote code execution (RCE) on the server. This vulnerability is fixed in 4.5.115.
How severe is CVE-2026-39890?: CVE-2026-39890 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39890 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39890?: CVE-2026-39890 affects Praison Praisonai. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39890?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-39890 have an EU (EUVD) identifier?: Yes. CVE-2026-39890 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20638.
When was CVE-2026-39890 published?: CVE-2026-39890 was published on 2026-04-08 and last updated on 2026-07-24.

References

https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-32vr-5gcf-3pw2

Affected products (1)

cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*

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