CVE-2026-40525
Volcengine Openviking ≤ 0.3.9
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-40525 is a critical-severity Failing Open (CWE-636) vulnerability in Volcengine Openviking. Its CVSS base score is 9.1 (Critical).
Operationally, ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to CP-12 (Safe Mode) and SC-24 (Fail in Known State) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-40525 is an authentication bypass vulnerability (CWE-636) in OpenViking versions prior to 0.3.9. The flaw exists in the VikingBot OpenAPI HTTP route surface, where the authentication check fails in an open state when the api_key configuration value is unset or empty. This allows unauthorized access to privileged functionality without a valid X-API-Key header.
Remote attackers with network access to an exposed OpenViking instance can exploit the vulnerability with low complexity and no privileges required. Successful exploitation enables invocation of bot-control features, such as submitting attacker-controlled prompts, creating or using bot sessions, and accessing downstream tools, integrations, secrets, or data available to the bot. The issue carries a CVSS v3.1 base score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N), indicating high confidentiality and integrity impacts.
Mitigation involves upgrading to OpenViking version 0.3.9 or later, which incorporates the fix via GitHub commit c7bb1676f4d037609f041bf39e4e2bd52e8f9820 and pull request #1447. Additional guidance is provided in the VulnCheck advisory at https://www.vulncheck.com/advisories/openviking-authentication-bypass-via-vikingbot-openapi.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-23464
Vulnerability Data
OpenViking prior to version 0.3.9 contains an authentication bypass vulnerability in the VikingBot OpenAPI HTTP route surface where the authentication check fails open when the api_key configuration value is unset or empty. Remote attackers with network access to the exposed…
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service can invoke privileged bot-control functionality without providing a valid X-API-Key header, including submitting attacker-controlled prompts, creating or using bot sessions, and accessing downstream tools, integrations, secrets, or data accessible to the bot.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
SC-24 directly requires the system to fail to a known state that preserves security properties, structurally stopping fallback to a less-secure mode.
SI-17 mandates explicit fail-safe procedures that activate on indicated failures, preventing the insecure fallback behavior.
CP-12 forces entry into a safe mode on detected conditions, limiting exposure but not covering every failure path.
SA-8 requires application of engineering principles that include fail-secure design, reducing the likelihood the weakness is introduced.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-636, a class-level weakness, and none of its children carries one either.