SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-30229

This allows a read-only credential to impersonate arbitrary users with full read and write access to their data.

HIGH 8.5EPSS 0.40%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.40%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.6 and 9.5.0-alpha.4, the readOnlyMasterKey can call POST /loginAs to obtain a valid session token for any user. This allows a read-only credential to impersonate arbitrary users with full read and write access to their data. Any Parse Server deployment that uses readOnlyMasterKey is affected. This issue has been patched in versions 8.6.6 and 9.5.0-alpha.4.

CVSS 4.0
8.5 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/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/M
EPSS
0.40% probability · 34th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-863
Affected
parseplatform/parse-server
Source
security-advisories@github.com
EPSS trend
0%3%5%26 October 2026: 0.40%26 October 202626 October 2026

EPSS 0.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.