CVE-2026-59239: Stored XSS in Prospero Flow CRM email body allows administrator account takeover

Severity: high (CVSS 8.6 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-27 · updated 2026-10-24
Weakness: CWE-79

Description

Stored Cross-site Scripting (CWE-79) in the email module in Roskus Prospero Flow CRM before 5.4.4 allows a remote, authenticated low-privileged user to execute arbitrary JavaScript in another user's browser, including administrators, leading to session compromise and account takeover, via a payload stored in an email body that is persisted without sanitization and rendered unescaped with {!! $email->body !!} when the recipient opens the message.

Affected products

Roskus Prospero Flow CRM: from 1.0.0 before 5.4.4 — fixed in 5.4.4

How to fix

Upgrade to a fixed version: Roskus Prospero Flow CRM 5.4.4. Check the vendor advisory for mitigations.

References

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