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

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

Which versions are affected by CVE-2026-82533?

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

How do I fix CVE-2026-82533?

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

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-82533 being exploited?

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

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-8m2g-8cgm-3vcp.