CVE-2026-34373 [Medium] | Security Bypass in Parse-Server

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.66 and 9.7.0-alpha.10, the GraphQL API endpoint does not respect the allowOrigin server option and unconditionally allows cross-origin requests from any website. This bypasses origin restrictions that operators configure to control which websites can interact with the Parse Server API. The REST API correctly enforces the configured allowOrigin restriction. This issue has been patched in versions 8.6.66 and 9.7.0-alpha.10.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.20%	+0.18%
2	2026-04-01	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.20%

+0.18%

2026-04-01

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.3	4.0	MEDIUM	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/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` 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:N) No privileges are required. User interaction (UI:P) A user has to participate (for example click/open/approve). Vulnerable system confidentiality impact (VC:N) No confidentiality impact on the vulnerable system. Vulnerable system integrity impact (VI:N) No integrity impact on the vulnerable system. Vulnerable system availability impact (VA:N) No availability impact on the vulnerable system. Subsequent system confidentiality impact (SC:L) Limited confidentiality impact on subsequent systems. Subsequent system integrity impact (SI:N) No 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]
8.8	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` 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:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.3

4.0

MEDIUM

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

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:N): No privileges are required.
User interaction (UI:P): A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:N): No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N): No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N): No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:L): Limited confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N): No 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]

8.8

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.9

[email protected]

Affected software / configurations for CVE-2026-34373

Vendor	Product	Version	Raw CPE
parseplatform	parse-server	>= 3.5.0, < 8.6.66	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
parseplatform	parse-server	>= 9.0.0, < 9.7.0	cpe:2.3:a:parseplatform:parse-server::::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha1::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha2::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha3::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha4::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha5::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha6::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha7::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha8::::node.js::*
parseplatform	parse-server	9.7.0	cpe:2.3:a:parseplatform:parse-server:9.7.0:alpha9::::node.js::*

References for CVE-2026-34373

URL	Tags
https://github.com/parse-community/parse-server/commit/0347641507891d0013ec57f7c10f012064f41263	Patch
https://github.com/parse-community/parse-server/commit/4dd0d3d8be1c39664c74ad10bb0abaa76bc41203	Patch
https://github.com/parse-community/parse-server/pull/10334	Issue Tracking Patch
https://github.com/parse-community/parse-server/pull/10335	Issue Tracking Patch
https://github.com/parse-community/parse-server/security/advisories/GHSA-q3p6-g7c4-829c	Patch Vendor Advisory

URL

CVE-2026-34373 | Parse Server: GraphQL API endpoint ignores CORS origin restriction

Exploit prediction scoring system (EPSS) score for CVE-2026-34373

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34373

Weakness enumeration for CVE-2026-34373

GitHub Security Advisory for CVE-2026-34373

Affected software / configurations for CVE-2026-34373

References for CVE-2026-34373