# CVE-2026-82533: DeepSeek Harness < 0.1.2-alpha.1 Authentication Bypass via Host Header Spoofing

> Attackers can bypass authentication via Host header spoofing to execute arbitrary commands and escape sandboxes in DeepSeek Harness.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 8 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-8m2g-8cgm-3vcp

## What is CVE-2026-82533?

CVE-2026-82533 is a critical authentication bypass vulnerability in DeepSeek Harness, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

DeepSeek Harness before 0.1.2-alpha.1 contains an authentication bypass vulnerability that grants unauthenticated access to its local HTTP agent-control API by accepting a client-supplied loopback Host header in place of validating the actual TCP connection origin. On the default configuration, a confined tool-executed process can reach the loopback API without any port exposure and use it to escape its own OS sandbox, escalate to unconfined execution, and disable the approval prompt. When the port is externally reachable via tunnel, SSH forward, or reverse proxy, a remote attacker can exploit the same flaw to create sessions, execute arbitrary commands, and exfiltrate stored conversation transcripts without credentials.

Weakness: CWE-807 (Reliance on Untrusted Inputs in a Security Decision)

## Which versions are affected by CVE-2026-82533?

2 open source packages ship an affected version, including @deepseek-ai/dsh-client-connection.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@deepseek-ai/dsh-client-connection` | npm | All versions | 0.1.2-alpha.1 |
| `@deepseek-ai/dsh-client-connection` | npm | All versions | 0.1.2-alpha.1 |

## How do I fix CVE-2026-82533?

Upgrade @deepseek-ai/dsh-client-connection to 0.1.2-alpha.1 or later.

## Is CVE-2026-82533 being exploited?

There is no known exploitation of CVE-2026-82533 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82533 and fix it if it is affected.

What it is: CVE-2026-82533 is a critical authentication bypass vulnerability in DeepSeek Harness, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-82533 in the wild and no public exploit code.

Affected packages and fixed versions:
- @deepseek-ai/dsh-client-connection (npm): affected all versions; fixed in 0.1.2-alpha.1
- @deepseek-ai/dsh-client-connection (npm): affected all versions; fixed in 0.1.2-alpha.1

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-2026-82533/ (Markdown: https://insights.sbomify.com/CVE-2026-82533/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82533
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82533
- OSV: https://osv.dev/vulnerability/CVE-2026-82533

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82533/
Summaries are generated and may contain mistakes; the official description above is the record.