CVE-2026-59821

—

CVSS 4.0

2.1 low

EPSS

<1%p49

Published

Jul 8, 2026 (Jul 8, 2026)

Modified

Jul 13, 2026

Description

LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. Prior to 1.82.0-stable, LiteLLM's Custom Code Guardrails production create and update paths did not apply the same sandboxing and validation used by the test endpoint, allowing a privileged user with access to create or update guardrails to submit custom Python code that executed in the LiteLLM proxy environment and could expose secrets available to the process. This issue is fixed in version 1.82.0-stable.

Vendors: litellm
Products: litellm
Weakness: CWE-94
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/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:X

NVD CVE.org GitHub PoCs EPSS (0.7%)

In the news4 stories

Off Guard: Breaking LiteLLM from authentication bypass to cloud compromise

Wiz found LiteLLM auth bypass (CVE-2026-59822) and post-auth RCE (CVE-2026-59821) chainable to cloud compromise; the bypass is in CISA KEV with in-the-wild exploitation.

Wiz scanned roughly 3,074 internet-facing LiteLLM deployments and found 9.6% accepted the default master key sk-1234 or required no authentication, making post-auth attacks effectively pre-auth. The MCP endpoint accepts any Bearer token and grants a valid session (CVE-2026-59822), confirmed exploited in the wild via honeypots and added to CISA's Known Exploited Vulnerabilities catalog. Custom code guardrails allow post-auth root-level RCE via exec(compile(...)) (CVE-2026-59821), while pass-through endpoints lack URL validation, enabling cloud credential theft in post-auth scenarios. All assigned vulnerabilities have been patched; the research was presented at DEF CON 34.

Wiz BlogSep 9, 16:06 UTC · 6d agoExploit / PoC in the wildCVE-2026-59822 CVE-2026-59821

Hackers Can Turn Vulnerable LiteLLM AI Gateways Into Root Access and Cloud Credential Theft

Wiz found multiple LiteLLM AI gateway flaws, including a CVE-2026-59822 MCP auth bypass added to CISA KEV, enabling root code execution and cloud credential theft.

An internet scan of 3,074 exposed LiteLLM instances found 294 (9.6%) accepting the default sk-1234 master key and 191 (6.2%) requiring no authentication. CVE-2026-59822 lets a single-character Bearer token establish a valid MCP session via an OAuth2 fallback in versions before 1.84.0; the flaw is in CISA's Known Exploited Vulnerabilities catalog. CVE-2026-59821 allows Python code execution as root in the gateway container via unsanitized Custom Code Guardrails registration before 1.82.0-stable, and CVE-2026-35029 permits config changes leading to RCE and admin takeover. Admin access plus pass-through endpoints can reach cloud metadata services to steal IAM credentials.

GBHackersSep 10, 12:56 UTC · 5d agoAI safety & security in the wildCVE-2026-59822 CVE-2026-59821 CVE-2026-35029

LiteLLM Flaws Let Attackers Execute Code as Root and Steal Cloud Credentials

Wiz disclosed LiteLLM flaws including CVE-2026-59822 MCP auth bypass, now in CISA KEV, enabling root RCE and AWS credential theft from exposed gateways.

Wiz researchers disclosed weaknesses in the open-source LiteLLM AI gateway: CVE-2026-59821 allows authenticated administrators to execute code as root via the Custom Code Guardrails feature, while CVE-2026-59822 is an MCP authentication bypass where a meaningless Bearer token establishes a valid session. The MCP bypass was observed in the wild through Wiz honeypots and added to CISA's Known Exploited Vulnerabilities catalog on September 2. A scan of 3,074 internet-facing instances found 294 (9.6%) accepting the default master key sk-1234 or lacking authentication. Fixes shipped in LiteLLM 1.82.0 (guardrail hardening) and 1.84.0 (MCP bypass); exposed instances can leak provider API keys and temporary AWS IAM credentials via the pass-through feature and metadata service, with a related config-check issue tracked as CVE-2026-35029.

Cyber Security NewsSep 10, 12:26 UTC · 5d agoExploit / PoC in the wildCVE-2026-59821 CVE-2026-59822 CVE-2026-35029

Nearly 1 in 10 Exposed LiteLLM Gateways Accepted the Example "sk-1234" Admin Key

Wiz found 294 of 3,074 internet-facing LiteLLM gateways accepted the documented default admin key sk-1234, exposing provider API keys and cloud IAM credentials.

Wiz Research's February Shodan scan found 3,074 LiteLLM gateways, 294 of which accepted the setup guide's sk-1234 admin key; 191 had no master key set and would accept any credential. The master key doubles as the authentication switch, and before 1.82.0-stable a gateway started without one granted every request full admin rights, exposing stored provider API keys, prompts, and MCP-connected tools. A documented pass-through endpoint lacks checks against private and cloud metadata addresses, letting an admin-key holder retrieve cloud IAM credentials, though no real-world abuse is reported. Related LiteLLM flaws include CVE-2026-59821 (disputed guardrail code execution), CVE-2026-59822 (CVSS 8.8, added to CISA KEV on September 2 and observed against Wiz honeypots), and CVE-2026-42271, used to install a cryptominer.

The Hacker NewsSep 10, 07:12 UTC · 5d agoVulnerability in the wildCVE-2026-59821 CVE-2026-59822 CVE-2026-42271+2 CVEs