How severe is CVE-2026-40586?

CVE-2026-40586 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-40586 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40586?

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

Does CVE-2026-40586 have an EU (EUVD) identifier?

Yes. CVE-2026-40586 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24182.

When was CVE-2026-40586 published?

CVE-2026-40586 was published on 2026-04-21 and last updated on 2026-06-17.

CVE-2026-40586

CVE-2026-40586 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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-307.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-24182
Weakness: CWE-307
Published: 2026-04-21
Last modified: 2026-06-17

Description

blueprintUE is a tool to help Unreal Engine developers. Prior to 4.2.0, the login form handler performs no throttling of any kind. Failed authentication attempts are processed at full network speed with no IP-based rate limiting, no per-account attempt counter, no temporary lockout, no progressive delay (Tarpit), and no CAPTCHA challenge. An attacker can submit an unlimited number of credential guesses. The password policy (10+ characters, mixed case, digit, special character) reduces the effective keyspace but does not prevent dictionary attacks, credential stuffing from breached databases, or targeted attacks against known users with predictable passwords. This vulnerability is fixed in 4.2.0.

Frequently asked questions

What is CVE-2026-40586?: blueprintUE is a tool to help Unreal Engine developers. Prior to 4.2.0, the login form handler performs no throttling of any kind. Failed authentication attempts are processed at full network speed with no IP-based rate limiting, no per-account attempt counter, no temporary lockout, no progressive delay (Tarpit), and no CAPTCHA challenge. An attacker can submit an unlimited number of credential guesses. The password policy (10+ characters, mixed case, digit, special character) reduces the effective keyspace but does not prevent dictionary attacks, credential stuffing from breached databases, or targeted attacks against known users with predictable passwords. This vulnerability is fixed in 4.2.0.
How severe is CVE-2026-40586?: CVE-2026-40586 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-40586 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40586?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40586 have an EU (EUVD) identifier?: Yes. CVE-2026-40586 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24182.
When was CVE-2026-40586 published?: CVE-2026-40586 was published on 2026-04-21 and last updated on 2026-06-17.

References

https://github.com/blueprintue/blueprintue-self-hosted-edition/security/advisories/GHSA-m6c2-6p3h-8jv2

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