How severe is CVE-2026-27641?

CVE-2026-27641 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-2026-27641 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27641?

CVE-2026-27641 affects Jugmac00 Flask-reuploaded. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27641?

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-2026-27641 have an EU (EUVD) identifier?

Yes. CVE-2026-27641 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8616.

When was CVE-2026-27641 published?

CVE-2026-27641 was published on 2026-02-25 and last updated on 2026-06-17.

CVE-2026-27641

CVE-2026-27641 is a critical-severity vulnerability in Jugmac00 Flask-reuploaded 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-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8616
Weakness: CWE-22
Affected product: Jugmac00 Flask-reuploaded
Published: 2026-02-25
Last modified: 2026-06-17

Description

Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.

Frequently asked questions

What is CVE-2026-27641?: Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.
How severe is CVE-2026-27641?: CVE-2026-27641 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-2026-27641 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27641?: CVE-2026-27641 affects Jugmac00 Flask-reuploaded. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27641?: 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-2026-27641 have an EU (EUVD) identifier?: Yes. CVE-2026-27641 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8616.
When was CVE-2026-27641 published?: CVE-2026-27641 was published on 2026-02-25 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:jugmac00:flask-reuploaded:*:*:*:*:*:python:*:*

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