What’s Vulnerable › Vulnerabilities

CVE-2026-48170: scimPatch vulnerable to prototype pollution via unfiltered keys in patch

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-07 · updated 2026-10-23
• Weakness: CWE-1321

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.

Affected products

• thomaspoignant scim-patch: before 0.9.1

References

• https://github.com/thomaspoignant/scim-patch/commit/260f9cd2ac5ceac3976978850bb47dcb391720f6
• https://github.com/thomaspoignant/scim-patch/security/advisories/GHSA-9m6g-wc8r-q59c
• https://github.com/thomaspoignant/scim-patch/security/advisories/GHSA-9m6g-wc8r-q59c

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