# CVE-2026-15699: spencermountain compromise Public Root API extend.js nlp.extend prototype pollution

> Remote attackers can achieve code execution via prototype pollution in the nlp.extend function of the compromise library.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-29jc-r7wj-73vf

## What is CVE-2026-15699?

CVE-2026-15699 is a medium-severity code injection vulnerability in spencermountain compromise, published on 14 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was identified in spencermountain compromise up to 14.15.1. Affected is the function nlp.extend of the file src/API/extend.js of the component Public Root API. The manipulation of the argument plugin leads to improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The exploit is publicly available and might be used. The identifier of the patch is b4644ab7179700df0607521f61c1ee9b5f78d89d. Applying a patch is the recommended action to fix this issue. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-15699?


## How do I fix CVE-2026-15699?

No fix has been published for CVE-2026-15699 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-15699 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15699 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15699 and fix it if it is affected.

What it is: CVE-2026-15699 is a medium-severity code injection vulnerability in spencermountain compromise, published on 14 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15699 exists.

Affected product: spencermountain compromise. 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-2026-15699/ (Markdown: https://insights.sbomify.com/CVE-2026-15699/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15699
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15699
- OSV: https://osv.dev/vulnerability/CVE-2026-15699

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15699/
Summaries are generated and may contain mistakes; the official description above is the record.