How severe is CVE-2025-43931?

CVE-2025-43931 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-2025-43931 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-43931?

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-2025-43931 have an EU (EUVD) identifier?

Yes. CVE-2025-43931 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-20241.

When was CVE-2025-43931 published?

CVE-2025-43931 was published on 2025-07-07 and last updated on 2026-06-17.

CVE-2025-43931

CVE-2025-43931 is a critical-severity vulnerability 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-640.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-20241
Weakness: CWE-640
Published: 2025-07-07
Last modified: 2026-06-17

Description

flask-boilerplate through a170e7c allows account takeover via the password reset feature because SERVER_NAME is not configured and thus a reset depends on the Host HTTP header.

Frequently asked questions

What is CVE-2025-43931?: flask-boilerplate through a170e7c allows account takeover via the password reset feature because SERVER_NAME is not configured and thus a reset depends on the Host HTTP header.
How severe is CVE-2025-43931?: CVE-2025-43931 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-2025-43931 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-43931?: 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-2025-43931 have an EU (EUVD) identifier?: Yes. CVE-2025-43931 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-20241.
When was CVE-2025-43931 published?: CVE-2025-43931 was published on 2025-07-07 and last updated on 2026-06-17.

References

Other CWE-640 vulnerabilities

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