Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-40217 is a high-severity Unprotected Alternate Channel (CWE-420) vulnerability in Litellm Litellm. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Fallback Channels (T1008); ranked in the top 7% 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 SA-11 (Developer Testing and Evaluation) and SC-8 (Transmission Confidentiality and Integrity) — 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-2026-40217 is a critical vulnerability in LiteLLM versions through 2026-04-08 that enables remote attackers to execute arbitrary code through bytecode rewriting at the /guardrails/test_custom_code URI. Classified under CWE-420, it carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant impact across confidentiality, integrity, and availability.
The vulnerability can be exploited by remote attackers with low privileges over the network, requiring low attack complexity and no user interaction. Successful exploitation grants attackers the ability to execute arbitrary code on the affected system, potentially leading to full compromise including data theft, modification, or disruption of services.
The primary advisory from x41-dsec, available at https://www.x41-dsec.de/lab/advisories/x41-2026-001-litellm/, provides further details on the issue. Security practitioners should consult this reference for recommended mitigations and patches.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21376
Vulnerability Data
LiteLLM through 2026-04-08 allows remote attackers to execute arbitrary code via bytecode rewriting at the /guardrails/test_custom_code URI.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation finds code paths that accept and execute externally influenced strings.
Transmission confidentiality and integrity requirements apply to all transmitted data, preventing weaker protection on secondary channels.
Input validation directly stops untrusted data from being used to construct executable code without neutralization.
Information flow enforcement requires consistent authorization and control over every path, directly stopping unequal protection of alternate channels.
Least privilege limits the damage an injected code fragment can perform once executed.
Requiring documented secure development standards and tools enforces use of safe code-generation APIs and escaping.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Protecting all data-in-transit directly mitigates unequal channel protection though the control addresses broader transit scenarios.
Network protection from unauthorized access inherently requires securing every channel, not just primaries.
PR.PS-06's SDLC practices directly target injection flaws via secure coding and testing (mostly), yet as a single broad outcome it leaves many code-generation specifics unaddressed (partial).
Network monitoring can surface use of unprotected alternate channels but does not prevent the design flaw.
PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Access restrictions may cover primary paths but leave alternate channels unprotected unless explicitly extended.
Secure authentication applies to primary channels but does not ensure alternate channels receive the same strength.
Network security controls ensure all channels receive equivalent protection, directly addressing unprotected alternate channels.
Security of network services requires consistent protection across all service channels, mitigating alternate-channel weaknesses.
Network segregation can reduce exposure of alternate channels but does not guarantee equivalent protection levels.
Banning unapproved code samples and unauthenticated web services, combined with secure-coding standards and SAST, prevents the dynamic generation or inclusion of attacker-supplied code.