CVE-2026-33527 [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 8.6.57 and 9.6.0-alpha.48, an authenticated user can overwrite server-generated session fields such as expiresAt and createdWith when updating their own session via the REST API. This allows bypassing the server's configured session lifetime policy, making a session effectively permanent. This issue has been patched in versions 8.6.57 and 9.6.0-alpha.48.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-25	—	0.01%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-25

—

0.01%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.3	4.0	MEDIUM	`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/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` 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:N) No user interaction is required. Vulnerable system confidentiality impact (VC:N) No 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:N) No 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]
4.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful 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	1.4	[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:L/UI:N/VC:N/VI:L/VA:N/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

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:N): No user interaction is required.
Vulnerable system confidentiality impact (VC:N): No 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:N): No 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]

4.3

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful 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

1.4

[email protected]

Affected software / configurations for CVE-2026-33527

Vendor	Product	Version	Raw CPE
parseplatform	parse-server	< 8.6.57	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:alpha15::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha16::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha17::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha18::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha19::::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:alpha20::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha21::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha22::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha23::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha24::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha25::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha26::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha27::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha28::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha29::::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:alpha30::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha31::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha32::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha33::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha34::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha35::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha36::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha37::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha38::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha39::::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:alpha40::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha41::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha42::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha43::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha44::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha45::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha46::::node.js::*
parseplatform	parse-server	9.6.0	cpe:2.3:a:parseplatform:parse-server:9.6.0:alpha47::::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-2026-33527

URL	Tags
https://github.com/parse-community/parse-server/commit/26b628c8fb3cc79ea955374769eebcff6f8a8a73	Patch
https://github.com/parse-community/parse-server/commit/ea68fc0b22a6056c9675149469ff57817f7cf984	Patch
https://github.com/parse-community/parse-server/pull/10263	Issue Tracking
https://github.com/parse-community/parse-server/pull/10264	Issue Tracking
https://github.com/parse-community/parse-server/security/advisories/GHSA-jc39-686j-wp6q	Vendor Advisory

URL

CVE-2026-33527 | Parse Server: Session update endpoint allows overwriting server-generated session fields

Exploit prediction scoring system (EPSS) score for CVE-2026-33527

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33527

Weakness enumeration for CVE-2026-33527

GitHub Security Advisory for CVE-2026-33527

Affected software / configurations for CVE-2026-33527

References for CVE-2026-33527