How severe is CVE-2026-34939?

CVE-2026-34939 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-34939 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34939?

CVE-2026-34939 affects Praison Praisonai. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34939?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34939 have an EU (EUVD) identifier?

Yes. CVE-2026-34939 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18921.

When was CVE-2026-34939 published?

CVE-2026-34939 was published on 2026-04-03 and last updated on 2026-06-17.

CVE-2026-34939

CVE-2026-34939 is a medium-severity vulnerability in Praison Praisonai with a CVSS 3.x base score of 6.5. 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-1333.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18921
Weakness: CWE-1333
Affected product: Praison Praisonai
Published: 2026-04-03
Last modified: 2026-06-17

Description

PraisonAI is a multi-agent teams system. Prior to version 4.5.90, MCPToolIndex.search_tools() compiles a caller-supplied string directly as a Python regular expression with no validation, sanitization, or timeout. A crafted regex causes catastrophic backtracking in the re engine, blocking the Python thread for hundreds of seconds and causing a complete service outage. This issue has been patched in version 4.5.90.

Frequently asked questions

What is CVE-2026-34939?: PraisonAI is a multi-agent teams system. Prior to version 4.5.90, MCPToolIndex.search_tools() compiles a caller-supplied string directly as a Python regular expression with no validation, sanitization, or timeout. A crafted regex causes catastrophic backtracking in the re engine, blocking the Python thread for hundreds of seconds and causing a complete service outage. This issue has been patched in version 4.5.90.
How severe is CVE-2026-34939?: CVE-2026-34939 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-34939 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34939?: CVE-2026-34939 affects Praison Praisonai. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34939?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34939 have an EU (EUVD) identifier?: Yes. CVE-2026-34939 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18921.
When was CVE-2026-34939 published?: CVE-2026-34939 was published on 2026-04-03 and last updated on 2026-06-17.

References

https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f

Affected products (1)

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

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