EUVD-2026-40007
GHSA-g2q4-cj5p-88qg
Severity by source
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/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
Network-accessible attack requires cookie interception as prerequisite (AC:H); no prior privileges needed to receive the token (PR:N); impact is limited to partial confidentiality from hash slot leakage with no integrity or availability consequence.
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
6DescriptionCVE.org
A vulnerability was found in SimStudioAI sim up to 0.6.92. Affected by this vulnerability is an unknown functionality in the library apps/sim/lib/core/security/deployment.ts of the component Password Protection Handler. Performing a manipulation results in use of weak hash. The attack is possible to be carried out remotely. The attack's complexity is rated as high. The exploitation appears to be difficult. The exploit has been made public and could be used. The pull request to fix this issue awaits acceptance.
AnalysisAI
Deployment authentication token weakness in SimStudioAI Sim up to 0.6.92 leaks a truncated SHA-256 derivative of the encrypted deployment password inside base64-encoded auth cookies, enabling offline hash cracking and potential token forgery against password-protected deployments. The vulnerable Password Protection Handler embeds only the first 8 hex characters (32 bits) of an unsalted SHA-256 hash of the encrypted password directly in the unprotected token payload - a CWE-328 use of weak hash - allowing an attacker who obtains the cookie to brute-force the narrow hash space and fingerprint or bypass deployment authentication. No patch has been merged; fix PR #4760 is pending acceptance, and a public proof-of-concept is available at https://github.com/simstudioai/sim/issues/4759.
Technical ContextAI
The vulnerable component is apps/sim/lib/core/security/deployment.ts within the SimStudioAI Sim Next.js-based AI agent builder. The Password Protection Handler issues authentication cookies for password-protected agent deployments. Legacy tokens encoded a passwordSlot - constructed as the first 8 hex characters of SHA-256(encryptedPassword) - directly in the base64 token payload using the format deploymentId:type:timestamp:passwordSlot. CWE-328 (Use of Weak Hash) applies on three counts: the output is truncated to 32 bits, collapsing the hash space to approximately 4 billion candidates; the hash is unsalted and unkeyed, making offline dictionary and brute-force attacks straightforward; and the legacy token format lacked an HMAC integrity signature, meaning unsigned forged tokens could be constructed. The PR diff confirms the fix introduces v2 tokens that bind the full SHA-256 password hash as part of an HMAC-SHA256 signature without exposing any password-derived value in the token body, and adds 24-hour TTL validation. CPE: cpe:2.3:a:simstudioai:sim:*:*:*:*:*:*:*:*.
RemediationAI
No officially merged or released patch exists at time of analysis - fix PR #4760 (https://github.com/simstudioai/sim/pull/4760) is pending acceptance. Operators should monitor the repository and upgrade immediately upon release of a patched version that incorporates the v2 token format with HMAC-SHA256 binding. As an interim compensating control, consider disabling the Password Protection feature on deployed agents if not operationally required, eliminating the vulnerable code path entirely. If password protection must remain enabled, rotate deployment passwords frequently (daily or per-session) to reduce the exploitation window from any leaked hash slot; note this does not prevent the hash truncation weakness itself but limits its usefulness. Ensure all deployment auth cookies are transmitted exclusively over HTTPS with Secure and HttpOnly flags set to prevent cookie interception - a prerequisite for exploitation. Review cookie issuance logs for anomalous access patterns that might indicate token forging attempts.
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Same weakness CWE-328 – Use of Weak Hash
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External POC / Exploit Code
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