CVE-2026-32728 [High] | XSS in Parse-Server

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.15 and 8.6.41, an attacker who is allowed to upload files can bypass the file extension filter by appending a MIME parameter (e.g. `;charset=utf-8`) to the `Content-Type` header. This causes the extension validation to fail matching against the blocklist, allowing active content to be stored and served under the application's domain. In addition, certain XML-based file extensions that can render scripts in web browsers are not included in the default blocklist. This can lead to stored XSS attacks, compromising session tokens, user credentials, or other sensitive data accessible via the browser's local storage. The fix in versions 9.6.0-alpha.15 and 8.6.41 strips MIME parameters from the `Content-Type` header before validating the file extension against the blocklist. The default blocklist has also been extended to include additional XML-based extensions (`xsd`, `rng`, `rdf`, `rdf+xml`, `owl`, `mathml`, `mathml+xml`) that can render active content in web browsers. Note that the `fileUpload.fileExtensions` option is intended to be configured as an allowlist of file extensions that are valid for a specific application, not as a denylist. The default denylist is provided only as a basic default that covers most common problematic extensions. It is not intended to be an exhaustive list of all potentially dangerous extensions. Developers should not rely on the default value, as new extensions that can render active content in browsers might emerge in the future. As a workaround, configure the `fileUpload.fileExtensions` option to use an allowlist of only the file extensions that your application needs, rather than relying on the default blocklist.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-20	0.05%	0.03%	-0.02%
2	2026-03-19	—	0.05%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-20

0.05%

0.03%

-0.02%

2026-03-19

—

0.05%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.3	4.0	HIGH	`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/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` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network. Attack complexity (AC:L) Exploitation conditions are straightforward and stable. Attack requirements (AT:N) No additional preconditions are required beyond normal reachability. Privileges required (PR:L) Low privileges are required. User interaction (UI:P) A user has to participate (for example click/open/approve). Vulnerable system confidentiality impact (VC:H) High confidentiality impact on the vulnerable system. Vulnerable system integrity impact (VI:L) Limited integrity impact on the vulnerable system. Vulnerable system availability impact (VA:N) No availability impact on the vulnerable system. Subsequent system confidentiality impact (SC:H) High confidentiality impact on subsequent systems. Subsequent system integrity impact (SI:L) Limited integrity impact on subsequent systems. Subsequent system availability impact (SA:N) No availability impact on subsequent systems. Exploit maturity (threat) (E:X) Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked). Confidentiality requirement (CR:X) Not defined: insufficient information; scoring treats this like High (worst case). Integrity requirement (IR:X) Not defined: insufficient information; scoring treats this like High (worst case). Availability requirement (AR:X) Not defined: insufficient information; scoring treats this like High (worst case). Modified attack vector (MAV:X) Not defined: scoring uses the Base Attack Vector (AV). Modified attack complexity (MAC:X) Not defined: scoring uses the Base Attack Complexity (AC). Modified attack requirements (MAT:X) Not defined: scoring uses the Base Attack Requirements (AT). Modified privileges required (MPR:X) Not defined: scoring uses the Base Privileges Required (PR). Modified user interaction (MUI:X) Not defined: scoring uses the Base User Interaction (UI). Modified vulnerable system confidentiality impact (MVC:X) Not defined: scoring uses the Base VC metric. Modified vulnerable system integrity impact (MVI:X) Not defined: scoring uses the Base VI metric. Modified vulnerable system availability impact (MVA:X) Not defined: scoring uses the Base VA metric. Modified subsequent system confidentiality impact (MSC:X) Not defined: scoring uses the Base SC metric. Modified subsequent system integrity impact (MSI:X) Not defined: scoring uses the Base SI metric. Modified subsequent system availability impact (MSA:X) Not defined: scoring uses the Base SA metric. Safety (supplemental) (S:X) Not evaluated. Automatable (supplemental) (AU:X) Not evaluated. Recovery (supplemental) (R:X) Not evaluated. Value density (supplemental) (V:X) Not evaluated. Vulnerability response effort (supplemental) (RE:X) Not evaluated. Provider urgency (supplemental) (U:X) Not evaluated.	—	—	[email protected]
7.6	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:L/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:L) A normal user session is enough; they don’t have to be admin. 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.	2.3	4.7	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.3

4.0

HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/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

Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L): Exploitation conditions are straightforward and stable.
Attack requirements (AT:N): No additional preconditions are required beyond normal reachability.
Privileges required (PR:L): Low privileges are required.
User interaction (UI:P): A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:H): High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L): Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N): No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:H): High confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:L): Limited integrity impact on subsequent systems.
Subsequent system availability impact (SA:N): No availability impact on subsequent systems.
Exploit maturity (threat) (E:X): Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X): Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X): Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X): Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X): Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X): Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X): Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X): Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X): Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X): Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X): Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X): Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X): Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X): Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X): Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X): Not evaluated.
Automatable (supplemental) (AU:X): Not evaluated.
Recovery (supplemental) (R:X): Not evaluated.
Value density (supplemental) (V:X): Not evaluated.
Vulnerability response effort (supplemental) (RE:X): Not evaluated.
Provider urgency (supplemental) (U:X): Not evaluated.

—

[email protected]

7.6

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/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:L): A normal user session is enough; they don’t have to be admin.
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.

2.3

4.7

[email protected]

Affected software / configurations for CVE-2026-32728

Vendor	Product	Version	Raw CPE
parseplatform	parse-server	< 8.6.41	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
parseplatform	parse-server	>= 9.0.0, < 9.6.0	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha1::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha10::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha11::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha12::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha13::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha14::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha2::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha3::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha4::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha5::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha6::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha7::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha8::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha9::::node.js::*

References for CVE-2026-32728

URL	Tags
https://github.com/parse-community/parse-server/commit/4f53ab3cad5502a51a509d53f999e00ff7217b8d	Patch
https://github.com/parse-community/parse-server/commit/c7599c577a02b97eb5e76d4e20517b0283ae73c8	Patch
https://github.com/parse-community/parse-server/pull/10191	Issue Tracking
https://github.com/parse-community/parse-server/pull/10192	Issue Tracking
https://github.com/parse-community/parse-server/security/advisories/GHSA-42ph-pf9q-cr72	Vendor Advisory

URL

CVE-2026-32728 | Parse Server has a stored XSS filter bypass via Content-Type MIME parameter and missing XML extension blocklist entries

Exploit prediction scoring system (EPSS) score for CVE-2026-32728

Common vulnerability scoring system (CVSS) metrics for CVE-2026-32728

Weakness enumeration for CVE-2026-32728

GitHub Security Advisory for CVE-2026-32728

Affected software / configurations for CVE-2026-32728

References for CVE-2026-32728