CVE-2026-34532

CRITICALCVSS 9.1/10EPSS 0.28%

Last modified

CVE-2026-34532 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.67 and 9.7.0-alpha.11, an attacker can bypass Cloud Function validator access controls by appending "prototype.constructor" to the function name in the URL. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.67 and 9.7.0-alpha.11, an attacker can bypass Cloud Function validator access controls by appending "prototype.constructor" to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped. This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic. This issue has been patched in versions 8.6.67 and 9.7.0-alpha.11.

Metrics

CVSS 3.1
9.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS 4.0
9.1/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.28%

19.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
ParseplatformParse-Server< 8.6.67
ParseplatformParse-Server>= 9.0.0, < 9.7.0
ParseplatformParse-Server9.7.0Alpha1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-34532?
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.67 and 9.7.0-alpha.11, an attacker can bypass Cloud Function validator access controls by appending "prototype.constructor" to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped. This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic. This issue has been patched in versions 8.6.67 and 9.7.0-alpha.11.
How severe is CVE-2026-34532?
CVE-2026-34532 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2026-34532?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34532?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST