CVE-2026-57858

Severity CVSS v4.0:

CRITICAL

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

12/08/2026

Last modified:

13/08/2026

Description

Cal.com Cal.diy versions 2.1.1 through 6.2.0 contain a stored cross-site scripting vulnerability in the BookingPageTagManager component that allows authenticated event owners to inject arbitrary JavaScript by supplying a malicious analytics tracking ID without sanitization. Attackers can close the inline script string literal with a crafted payload that executes in the browser of every visitor to the affected public booking page, enabling session cookie theft, forged authenticated requests, and wormable propagation by chaining with CSRF-able endpoints to persist payloads on additional events.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L CVSS v4.0 Severity and Metrics:

Base Score: 9.30 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): Active
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): Low
Confidentiality (SC): High
Integrity (SI): High
Availability (SA): Low

Base Score 4.0

9.30

Severity 4.0

CRITICAL

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L CVSS v3.1 Severity and Metrics:

Base Score: 8.90 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): Low

Base Score 3.x

8.90

Severity 3.x

HIGH

CVE-2026-57858

Description

Impact

References to Advisories, Solutions, and Tools