Description

OliveTin gives access to predefined shell commands from a web interface. The `filterToDefinedArgumentsOnly` function in the executor is intended to discard any arguments not explicitly defined in the action's configuration. However, prior to commit ebffd9f040f791208aee1db2e5a8aecd1e3e603d, a special case allows any argument whose name starts with `ot_` to bypass this filter. While two system arguments (`ot_executionTrackingId` and `ot_username`) are injected by OliveTin and overridden, all other `ot_`-prefixed arguments supplied by the user pass through unmodified. These bypassed arguments are not type-checked — the validation loop only iterates over the action's defined arguments, so `ot_`-prefixed arguments skip all type safety checks entirely; set as environment variables — via `buildEnv()`, with completely unvalidated values, and passed to the executed command; and included in the template context — available as `.Arguments.ot_*` in template rendering. Commit ebffd9f040f791208aee1db2e5a8aecd1e3e603d contains a patch.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-21T23:16:26.500Z",
  "pubdate": "2026-08-21T23:16:26.500Z",
  "executiveSummary": "OliveTin contains an argument filter bypass vulnerability within its execution handler that allows remote users to supply arbitrary parameters to underlying shell commands.\nThe vulnerability affects OliveTin deployments utilizing versions prior to commit ebffd9f040f791208aee1db2e5a8aecd1e3e603d.\nThe root cause stems from an overly permissive exception in the filterToDefinedArgumentsOnly function, which permits any user-supplied argument beginning with the ot_ prefix to completely bypass validation checks.\nAttackers can leverage this behavior to inject arbitrary values that bypass type safety constraints, become exposed as environment variables via the buildEnv() mechanism, and populate the template rendering context.\nSuccessful exploitation allows unauthorized manipulation of environment variables and injected command parameters, potentially leading to arbitrary command execution or logic corruption depending on how the downstream shell scripts consume the environment.\nThe risk implication is high as it compromises the execution boundaries defined in the action configurations.\nExploitation requires network access to the OliveTin web interface and the ability to trigger actions that process user inputs.",
  "technicalDetails": "The vulnerability resides in the executor component of OliveTin, specifically within the filterToDefinedArgumentsOnly function responsible for sanitizing and validating inputs against predefined action configurations.\nPrior to commit ebffd9f040f791208aee1db2e5a8aecd1e3e603d, the validation logic contained a special case granting an unconditional bypass for any argument name starting with the ot_ prefix.\nAlthough OliveTin internally injects and overrides two specific system arguments named ot_executionTrackingId and ot_username, all other arbitrary ot_ arguments supplied by an external user are permitted to pass through the filter unmodified.\nThe attack flow proceeds as follows: First, an attacker interacts with the OliveTin web interface and crafts a request containing custom parameters prefixed with ot_. Second, the filterToDefinedArgumentsOnly function encounters these parameters and permits them to bypass the validation loop, which exclusively iterates over explicitly defined action arguments.\nAs a result, these bypassed arguments completely skip all associated type safety checks and constraints.\nThird, the unvalidated argument values are processed by the buildEnv() function, which sets them as environment variables destined for the executed shell command.\nFinally, these arguments are simultaneously included in the template context, making them accessible as .Arguments.ot_* during template rendering.\nThe vulnerable component is the argument filtering and environment construction pipeline within the executor.\nAuthentication and privilege requirements depend on the specific OliveTin deployment configuration, but network exposure is inherent to the web interface.\nPost-exploitation impact includes the injection of arbitrary environment variables into subprocesses, which can alter application behavior, inject malicious configurations, or facilitate command injection if downstream shell commands insecurely parse the injected environment."
}