CVE-2025-3197

expand-object Vulnerable to Prototype Pollution via the expand() Function

6.9 Medium

Versions of the package expand-object from 0.0.0 are vulnerable to Prototype Pollution in the expand() function in index.js. This function expands the given string into an object and allows a nested property to be set without checking the provided keys for sensitive properties like proto.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: Low

Exploit likelihood

0.42%Up 0.4 points since Apr 4, 2025

What each source reports

CVE List Score used 6.9

Record: CVE-2025-3197
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
CVSS 3.1: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-1321, CWE-1321
Updated: 2026-11-02

EUVDEUVD-2025-9700 6.9

Record: EUVD-2025-9700
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
Updated: 2026-11-02

GitHub AdvisoriesGHSA-4vjr-hfpp-2m7w 5.5

expand-object Vulnerable to Prototype Pollution via the expand() Function

Versions of the package expand-object from 0.0.0 to 0.4.2 are vulnerable to Prototype Pollution in the expand() function in index.js. This function expands the given string into an object and allows a nested property to be set without checking the provided keys for sensitive properties like proto.

Record: GHSA-4vjr-hfpp-2m7w
CVSS 4.0: 5.5 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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
CVSS 3.1: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-1321
Updated: 2026-11-02

NVD 5.5

Record: CVE-2025-3197
CVSS 4.0: 5.5 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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
CVSS 3.1: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-1321
Updated: 2026-11-02

OSVGHSA-4vjr-hfpp-2m7w 5.5

expand-object Vulnerable to Prototype Pollution via the expand() Function

Record: GHSA-4vjr-hfpp-2m7w
CVSS 4.0: 5.5 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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
CVSS 3.1: 7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness: CWE-1321
Updated: 2026-11-02

Affected packages

Affected packages
Package	Affected	Fixed
`expand-object` npm	through 0.4.2	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-3197 is a medium vulnerability (CVSS 6.9) in expand-object, published April 4, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. No source names a fixed version.