# CVE-2026-51538: Auth bypass in n/a

> Attackers can hijack sessions by reusing valid handles from other clients, bypassing access controls in OpENer industrial protocol stacks.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Jul 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-jcwf-w8h2-gq3f

## What is CVE-2026-51538?

CVE-2026-51538 is a critical authentication bypass vulnerability in n/a, published on 13 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

EIPStackGroup OpENer 2.3.0 (commit 76b95cf) suffers from an Incorrect Access Control vulnerability in its handling of encapsulation sessions. When the server processes critical encapsulation commands, it verifies whether the provided session_handle exists in the global session list, but it fails to verify whether that handle belongs to the specific TCP connection issuing the request. Because there is no strong binding between a session handle and its originating socket, any attacker on the network can use a valid session handle created by another legitimate client to bypass access controls.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-51538?

It affects 1 product.


Products: Opener Project Opener.

## How do I fix CVE-2026-51538?

No fix has been published for CVE-2026-51538 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-51538 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51538 exists.

## Other vulnerabilities in n/a

- [CVE-2022-43604](https://insights.sbomify.com/CVE-2022-43604/): Memory corruption in OpENer (critical 10.0)
- [CVE-2022-43605](https://insights.sbomify.com/CVE-2022-43605/): Memory corruption in OpENer (critical 10.0)
- [CVE-2026-51540](https://insights.sbomify.com/CVE-2026-51540/): Integer overflow in n/a (critical 9.8)
- [CVE-2020-13556](https://insights.sbomify.com/CVE-2020-13556/): Memory corruption in EIP Stack Group (critical 9.8)
- [CVE-2026-51536](https://insights.sbomify.com/CVE-2026-51536/): Integer overflow in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-51538 and fix it if it is affected.

What it is: CVE-2026-51538 is a critical authentication bypass vulnerability in n/a, published on 13 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-51538 exists.

Affected product: n/a. 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-2026-51538/ (Markdown: https://insights.sbomify.com/CVE-2026-51538/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-51538
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-51538
- OSV: https://osv.dev/vulnerability/CVE-2026-51538

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-51538/
Summaries are generated and may contain mistakes; the official description above is the record.