Vulnerability · Published Aug 21, 2026 · Assigned by GitHub_M

CVE-2026-53541OliveTin has Unvalidated `ot_`-prefixed Arguments that Bypass Input Filtering

Medium 4.3

In plain English

A medium-severity improper input validation in OliveTin from OliveTin. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.4%top 67.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/OliveTin/OliveTin0.0.0-20260531214440-ebffd9f040f7GHSA-prj9-97mp-mwh2
Gogithub.com/OliveTin/OliveTin0.0.0-20260531214440-ebffd9f040f7GO-2026-5552

Affected products (as reported)

VendorProductVersions
OliveTin OliveTin <= 2025.03.07

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

References