Authorization Bypass Through User-Controlled Key in Prospero Flow CRM calendar event deletion

published 2026-07-03 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-41539

cvss: 6.9; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits: 0; none known

Authorization Bypass Through User-Controlled Key (CWE-639) in CalendarDeleteEventController (app/Http/Controllers/Calendar/CalendarDeleteEventController.php), exposed at GET /calendar/event/delete/{id}, in Prospero Flow CRM before 5.5.3 allows a remote, authenticated attacker to delete arbitrary calendar events belonging to other users by manipulating the {id} path parameter, because the delete handler resolves the record with Calendar::find($id)->delete() and performs no ownership check (no user_id/company_id scoping) before deletion. This results in unauthorized destruction of other users' calendar events across the platform.

Patch / fix

fixed in 1 links 2

Roskus Prospero Flow CRM 5.5.3

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 4 mo ago (2026-07-06)

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
CNA	4.0	6.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Roskus Prospero Flow CRM

Classification

Weakness

CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

CVE List CVE-2026-59234
NVD CVE-2026-59234

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary