Vulnerability in Deepseek Harness
CVE-2026-82533
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.012 (68.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 68.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: +0.000
Affected products
Weakness classification (CWE)
References
- github.com/deepseek-ai/deepseek-harness/commit/3e24087bfaeabe40b58ba2f7b936895b… (patch)
- github.com/deepseek-ai/deepseek-harness/releases/tag/dsh-v0.1.2-alpha.1 (release-notes)
- www.vulncheck.com/advisories/deepseek-harness-alpha-1-authentication-bypass-via… (third-party-advisory)
- www.ox.security/blog/cve-2026-82533-deepseek-harness-ai-agent-sandbox-escape/ (technical-description, exploit)
Frequently asked questions
- What is CVE-2026-82533?
- CVE-2026-82533 is a critical-severity vulnerability in Deepseek Harness, classified under CWE-807. CVSS score: 9.6/10. Published 2026-09-08.
- How severe is CVE-2026-82533?
- Critical severity. CVSS v3 base score is 9.6 out of 10.