Prototype Pollution in Thomaspoignant Scim-Patch

CVE-2026-61834

scim-patch is a library for applying SCIM patch operations. Prior to 0.9.2, navigate() reads inherited properties and assign() uses prototype-chain membership checks while resolving attacker-controlled SCIM PATCH paths. A path or one of the dotted value keys beginning with an inherited property such as toString can therefore traverse into a shared built-in function object and add attacker-controlled properties, causing process-global mutation that may affect application logic reading inherited-method properties. This issue is fixed in version 0.9.2.

Vulnerability class: Mass Assignment

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (33.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 34th percentile — 33.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-61834: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-61834?
CVE-2026-61834 is a medium-severity vulnerability in Thomaspoignant Scim-Patch, classified under Improperly Controlled Modification of Dynamically-Determined Object Attributes. CVSS score: 4.3/10. Published 2026-09-23.
How severe is CVE-2026-61834?
Medium severity. CVSS v3 base score is 4.3 out of 10.