# CVE-2026-40434: Anviz CrossChex Standard Improper Verification of Source of a Communication Channel

> An attacker on the same network can inject TCP packets to alter or disrupt traffic in Anviz CrossChex Standard due to lack of source verification.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Apr 2026
- **Updated:** 17 Apr 2026
- **Also known as:** GHSA-qg37-cwrh-945r

## What is CVE-2026-40434?

CVE-2026-40434 is a high-severity vulnerability in Anviz CrossChex Standard, published on 17 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Anviz CrossChex Standard
lacks source verification in the client/server channel, enabling TCP 
packet injection by an attacker on the same network to alter or disrupt 
application traffic.

Weakness: CWE-940 (Improper Verification of Source of a Communication Channel)

## Which versions are affected by CVE-2026-40434?

It affects 1 product.


Products: Anviz Crosschex Standard.

## How do I fix CVE-2026-40434?

No fix has been published for CVE-2026-40434 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40434 being exploited?

There is no known exploitation of CVE-2026-40434 in the wild and no public exploit code.

## Other vulnerabilities in Anviz CrossChex Standard

- [CVE-2026-32650](https://insights.sbomify.com/CVE-2026-32650/): Anviz CrossChex Standard Algorithm Downgrade (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40434 and fix it if it is affected.

What it is: CVE-2026-40434 is a high-severity vulnerability in Anviz CrossChex Standard, published on 17 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40434 in the wild and no public exploit code.

Affected product: Anviz CrossChex Standard. 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-2026-40434/ (Markdown: https://insights.sbomify.com/CVE-2026-40434/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40434
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40434
- OSV: https://osv.dev/vulnerability/CVE-2026-40434

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40434/
Summaries are generated and may contain mistakes; the official description above is the record.