CVE-2026-73658 in Trigger.dev
Summary
by MITRE • 08/14/2026
Trigger.dev is a platform for building and deploying fully managed AI agents and workflows. From 4.4.2 until 4.5.0-rc.5, Aws4FetchClient.buildUrl() and Aws4FetchClient.presign() in apps/webapp/app/v3/objectStoreClient.server.ts assign user-controlled packet keys to URL.pathname, while apps/webapp/app/routes/api.v1.packets.$.ts accepts params["*"] without rejecting dot segments and uses findResource: async () => 1 without per-resource ownership validation. WHATWG path normalization collapses .. segments before signing, allowing a caller with a valid environment API key to obtain presigned URLs for another tenant's object-store keys and read or overwrite task payloads. This issue is fixed in version 4.5.0-rc.5.
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Analysis
by VulDB Data Team • 08/14/2026
The vulnerability in Trigger.dev affects versions 4.4.2 through 4.5.0-rc.5 and stems from improper handling of user-controlled data within the Aws4FetchClient implementation. The core flaw exists in how packet keys are processed when constructing URLs for object storage operations, specifically within the buildUrl() and presign() methods of the Aws4FetchClient class. These methods directly assign user-supplied packet key values to URL pathname components without adequate sanitization or validation, creating a path traversal risk that can be exploited by malicious actors.
The vulnerability manifests through a combination of weak input validation and insufficient access control mechanisms within the API endpoint handling. The api.v1.packets.$ route accepts params["*"] parameter values without proper filtering of dot segments, allowing attackers to manipulate path components in ways that bypass normal navigation constraints. Additionally, the findResource function operates without implementing per-resource ownership validation, meaning it returns a hardcoded value of 1 regardless of actual resource ownership or permissions. This design flaw creates a critical access control gap where any authenticated user with a valid environment API key can potentially access resources belonging to other tenants within the same system.
The technical exploitation relies on WHATWG path normalization behavior which collapses .. segments before cryptographic signing operations occur. This normalization process effectively neutralizes attempts to traverse directories using traditional path manipulation techniques, but only after the malicious path components have already been incorporated into the URL structure. Attackers can craft specially formatted packet keys that, when processed through the vulnerable buildUrl() and presign() methods, generate presigned URLs pointing to unintended object-store locations within the tenant namespace. This allows unauthorized access to read or overwrite task payloads belonging to different tenants.
This vulnerability aligns with CWE-22 Path Traversal and CWE-352 Cross-Site Request Forgery, representing a significant authorization bypass that could result in data exposure and potential data corruption across multiple tenant environments. The attack pattern follows ATT&CK technique T1078 Valid Accounts by leveraging legitimate API keys to access resources outside the intended scope. Organizations using affected versions of Trigger.dev face risks including unauthorized data access, information disclosure, and potential service disruption through malicious payload manipulation.
The security implications extend beyond simple data access, as this vulnerability could enable attackers to manipulate workflow execution contexts and potentially compromise the integrity of AI agent operations. Mitigation strategies should focus on implementing proper input validation for all user-controlled path components, enforcing strict per-resource ownership checks in resource lookup functions, and ensuring that all URL construction operations properly sanitize and validate path segments before cryptographic signing. Organizations should immediately upgrade to version 4.5.0-rc.5 or later where these issues have been addressed through improved parameter validation and access control enforcement mechanisms.