# CVE-2026-85625: sift 17.1.3 Prototype Pollution Remote Code Execution via $where

> Attackers can execute arbitrary JavaScript via prototype pollution or untrusted queries in sift.js due to unsafe $where operator handling.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-8pfg-3p4c-36vm

## What is CVE-2026-85625?

CVE-2026-85625 is a critical code injection vulnerability in crcn sift.js, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

sift (sift.js) 17.1.3 enumerates query keys with for...in, which walks the object prototype chain, and dispatches any matched operator key including $where. The $where operation compiles a string value into a function using new Function unless CSP_ENABLED is set (not set by default). As a result, if a prototype-pollution primitive elsewhere in the process sets Object.prototype.$where to a malicious string, even benign filter calls such as sift({}) execute arbitrary JavaScript. Additionally, passing an untrusted query object containing a string $where directly to sift results in code execution under the default configuration.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-85625?


## How do I fix CVE-2026-85625?

No fix has been published for CVE-2026-85625 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85625 being exploited?

There is no known exploitation of CVE-2026-85625 in the wild and no public exploit code.

Public exploit code:

- Security-hardened fork of sift 17.1.3 for CVE-2026-85625. Not affiliated with crcn/sift.js. (github_poc): https://github.com/lgranadoi/sift-hardened

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85625 and fix it if it is affected.

What it is: CVE-2026-85625 is a critical code injection vulnerability in crcn sift.js, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-85625 in the wild and no public exploit code.

Affected product: crcn sift.js. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-85625/ (Markdown: https://insights.sbomify.com/CVE-2026-85625/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85625
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85625
- OSV: https://osv.dev/vulnerability/CVE-2026-85625

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85625/
Summaries are generated and may contain mistakes; the official description above is the record.