scimPatch vulnerable to prototype pollution via unfiltered keys in patch (CVE-2026-48170) | HOL Guard CVE

Critical · CVSS 9.1CVE-2026-48170GHSA-9M6G-WC8R-Q59C

scimPatch vulnerable to prototype pollution via unfiltered keys in patch

Answer in brief

CVE-2026-48170 records a Critical severity (CVSS 9.1) vulnerability in scimPatch vulnerable to prototype pollution via unfiltered keys in patch. The current sources do not mark it as known exploited. The current feed maps thomaspoignant/scim-patch (generic), scim-patch (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 7, 2026Updated Aug 10, 2026Source checked Sep 17, 2026First seen by HOL Jun 22, 2026Material review Aug 10, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.1
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps thomaspoignant/scim-patch (generic), scim-patch (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
thomaspoignant/scim-patchgeneric	< 0.9.1	Not reported
scim-patchnpm	<=0.9.0	0.9.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for thomaspoignant/scim-patch, scim-patch.
Review the reported fix. Update scim-patch to 0.9.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 7, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 22, 2026

Sources and claim methodology

Upstream source description

`scim-patch`, a library to perform SCIM patch, prior to version 0.9.1 performs prototype pollution when applying a SCIM PATCH operation whose `value` object contains a key like `"__proto__.someProp"`. After one such patch, `Object.prototype.someProp` is set process-wide, affecting every plain object in the Node process. Any service that calls `scimPatch()` on attacker-controlled JSON (i.e. any SCIM endpoint accepting `PATCH` from an external IdP) is exploitable on a stock Node runtime. Version 0.9.1 contains a patch. A workaround is available. Calling `Object.freeze(Object.prototype)` (and the same on `Array.prototype`, `Function.prototype`) at process startup neutralizes this class of bug — assignment to a frozen prototype becomes a silent no-op in sloppy mode or a `TypeError` in strict mode. Node's `--frozen-intrinsics` flag does this for built-ins automatically.

Quoted source text, attributed separately from HOL analysis.