# CVE-2023-28807: Bypass of ZIA domain fronting detection module through evasion technique

> Attackers can bypass Zscaler Internet Access security controls by mismatching Connect Host and SNI to hide malicious traffic.

- **Severity:** Medium 5.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **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:** 31 Jan 2024
- **Updated:** 17 Jun 2025
- **Also known as:** GHSA-p774-6cp5-x7cj

## What is CVE-2023-28807?

CVE-2023-28807 is a medium-severity vulnerability in Zscaler ZIA, published on 31 Jan 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Zscaler Internet Access (ZIA) a mismatch between Connect Host and Client Hello's Server Name Indication (SNI) enables attackers to evade network security controls by hiding their communications within legitimate traffic.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2023-28807?

It affects 1 product.


Products: Zscaler Secure Internet and Saas Access.

## How do I fix CVE-2023-28807?

No fix has been published for CVE-2023-28807 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28807 being exploited?

There is no known exploitation of CVE-2023-28807 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28807 and fix it if it is affected.

What it is: CVE-2023-28807 is a medium-severity vulnerability in Zscaler ZIA, published on 31 Jan 2024. 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-2023-28807 in the wild and no public exploit code.

Affected product: Zscaler ZIA. 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-2023-28807/ (Markdown: https://insights.sbomify.com/CVE-2023-28807/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28807
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28807
- OSV: https://osv.dev/vulnerability/CVE-2023-28807

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28807/
Summaries are generated and may contain mistakes; the official description above is the record.