CVE-2025-66492 [High] | XSS in Masacms

Masa CMS is an open source Enterprise Content Management platform. Versions 7.2.8 and below, 7.3.1 through 7.3.13, 7.4.0-alpha.1 through 7.4.8 and 7.5.0 through 7.5.1 are vulnerable to XSS when an unsanitized value of the ajax URL query parameter is directly included within the <head> section of the HTML page. An attacker can execute arbitrary scripts in the context of the user's session, potentially leading to Session Hijacking, Data Theft, Defacement and Malware Distribution. This issue is fixed in versions 7.5.2, 7.4.9, 7.3.14, and 7.2.9. To work around this issue, configure a Web Application Firewall (WAF) rule (e.g., ModSecurity) to block requests containing common XSS payload characters in the ajax query parameter. Alternatively, implement server-side sanitization using middleware to strip or escape dangerous characters from the ajax parameter before it reaches the vulnerable rendering logic.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-22	0.04%	0.05%	+0.01%
2	2026-05-10	0.06%	0.04%	-0.01%
3	2026-02-18	—	0.06%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-22

0.04%

0.05%

+0.01%

2026-05-10

0.06%

0.04%

-0.01%

2026-02-18

—

0.06%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.2	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	4.7	[email protected]
6.1	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	2.7	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.2

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.8

4.7

[email protected]

6.1

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.8

2.7

[email protected]

Affected software / configurations for CVE-2025-66492

Vendor	Product	Version	Raw CPE
masacms	masacms	< 7.2.9	cpe:2.3:a:masacms:masacms::::::::
masacms	masacms	>= 7.3.1, < 7.3.14	cpe:2.3:a:masacms:masacms::::::::
masacms	masacms	>= 7.4.0, < 7.4.9	cpe:2.3:a:masacms:masacms::::::::
masacms	masacms	>= 7.5.0, < 7.5.2	cpe:2.3:a:masacms:masacms::::::::

References for CVE-2025-66492

URL	Tags
https://github.com/MasaCMS/MasaCMS/commit/376c27196b1e2489888b7a000cdf5c45bb85959e	Patch
https://github.com/MasaCMS/MasaCMS/security/advisories/GHSA-249c-vqwv-43vc	Patch Vendor Advisory

URL

CVE-2025-66492 | Masa CMS vulnerable to Cross-Site Scripting (XSS) through URL Parameter

Exploit prediction scoring system (EPSS) score for CVE-2025-66492

Common vulnerability scoring system (CVSS) metrics for CVE-2025-66492

Weakness enumeration for CVE-2025-66492

Affected software / configurations for CVE-2025-66492

References for CVE-2025-66492