# CVE-2026-26333: Calero VeraSMART < 2022 R1 .NET Remoting Arbitrary File Read Leading to ViewState RCE

> Unauthenticated attackers can exploit exposed .NET Remoting endpoints to read sensitive files and achieve remote code execution via ViewState deserialization.

- **Severity:** Critical 10.0 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Feb 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-m4w4-g5c5-j4f4

## What is CVE-2026-26333?

CVE-2026-26333 is a critical unsafe deserialization vulnerability in Calero VeraSMART, published on 13 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Calero VeraSMART versions prior to 2022 R1 expose an unauthenticated .NET Remoting HTTP service on TCP port 8001. The service publishes default ObjectURIs (including EndeavorServer.rem and RemoteFileReceiver.rem) and permits the use of SOAP and binary formatters with TypeFilterLevel set to Full. An unauthenticated remote attacker can invoke the exposed remoting endpoints to perform arbitrary file read and write operations via the WebClient class. This allows retrieval of sensitive files such as WebRoot\\web.config, which may disclose IIS machineKey validation and decryption keys. An attacker can use these keys to generate a malicious ASP.NET ViewState payload and achieve remote code execution within the IIS application context. Additionally, supplying a UNC path can trigger outbound SMB authentication from the service account, potentially exposing NTLMv2 hashes for relay or offline cracking.

Weakness: CWE-502 (Deserialization of Untrusted Data), CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-26333?

It affects 1 product.


Products: Calero Verasmart.

## How do I fix CVE-2026-26333?

No fix has been published for CVE-2026-26333 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-26333 being exploited?

There is no known exploitation of CVE-2026-26333 in the wild and no public exploit code.

## Other vulnerabilities in Calero VeraSMART

- [CVE-2026-26335](https://insights.sbomify.com/CVE-2026-26335/): Calero VeraSMART < 2022 R1 Static IIS Machine Keys Enable ViewState RCE (critical 9.3)
- [CVE-2026-26334](https://insights.sbomify.com/CVE-2026-26334/): Calero VeraSMART < 2026 R1 Hardcoded Static AES Keys Allow Decryption of Service Credentials (high 8.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26333 and fix it if it is affected.

What it is: CVE-2026-26333 is a critical unsafe deserialization vulnerability in Calero VeraSMART, published on 13 Feb 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-2026-26333 in the wild and no public exploit code.

Affected product: Calero VeraSMART. 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-2026-26333/ (Markdown: https://insights.sbomify.com/CVE-2026-26333/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26333
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26333
- OSV: https://osv.dev/vulnerability/CVE-2026-26333

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26333/
Summaries are generated and may contain mistakes; the official description above is the record.