CVE-2026-53541 is a medium-severity improper input validation vulnerability in github.com/OliveTin/OliveTin (go), affecting versions < 0.0.0-20260531214440-ebffd9f040f7. It is fixed in 0.0.0-20260531214440-ebffd9f040f7.
Description The filterToDefinedArgumentsOnly function in the executor is intended to discard any arguments not explicitly defined in the action's configuration. However, a special case allows any argument whose name starts with ot to bypass this filter. While two system arguments (otexecutionTrackingId and otusername) 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. Included in the template context, available as .Arguments.ot* in template rendering. Affected Code Filter bypass, service/internal/executor/executor.go (lines 728–731): System args only override two keys, service/internal/executor/executor.go (lines 742–745): Any other ot-prefixed argument (e.g., otmalicious) survives both functions. Unvalidated values become environment variables, service/internal/executor/executor.go (lines 867–882): The value v is never validated. It can contain newlines, shell metacharacters, null bytes, or any arbitrary data. Proof of Concept An attacker sends a StartAction request with extra ot-prefixed arguments: These arguments: Pass through filterToDefinedArgumentsOnly (the ot prefix exempts them). Are never type-checked (not in the action's argument definitions). Become environment variables OTCUSTOMVAR and OTANOTHER in the executed command's environment. Are available in the template rendering context as .Arguments.otcustomvar and .Arguments.otanother. Impact Environment variable pollution, attacker can set arbitrary environment variables (with OT uppercased prefix) in the execution environment of any action they can trigger. Scripts or programs that read custom environment variables could be influenced. Potential for secondary exploitation, if any executed script or command reads OT-prefixed environment variables, the unvalidated content could cause unexpected behavior. Template context pollution, although Go's text/template does not recursively evaluate data values (mitigating direct template injection), the extra arguments are accessible in the template context and could interact unexpectedly with custom template logic. Suggested Fix Remove the ot_ prefix exception from keepArgument, or restrict it to only the two known system arguments: Discovery Methodology Both vulnerabilities were identified through manual source code review of the OliveTin repository, focusing on: Input validation boundaries (API request fields flowing into file system operations and execution contexts) Argument filtering and type-checking logic in the executor File path construction in the log persistence feature No automated scanners or fuzzing tools were used. The review was conducted against the current main branch source code.
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
CVE-2026-53541 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (0.0.0-20260531214440-ebffd9f040f7). Upgrading removes the vulnerable code path.
go
github.com/OliveTin/OliveTin (< 0.0.0-20260531214440-ebffd9f040f7)github.com/OliveTin/OliveTin → 0.0.0-20260531214440-ebffd9f040f7 (go)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-53541 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-53541 is reachable in your applications. Get a demo
Already deployed Kodem? See CVE-2026-53541 in your environment →Upgrade github.com/OliveTin/OliveTin to 0.0.0-20260531214440-ebffd9f040f7 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-53541 is a medium-severity improper input validation vulnerability in github.com/OliveTin/OliveTin (go), affecting versions < 0.0.0-20260531214440-ebffd9f040f7. It is fixed in 0.0.0-20260531214440-ebffd9f040f7. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
CVE-2026-53541 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
github.com/OliveTin/OliveTin (go) versions < 0.0.0-20260531214440-ebffd9f040f7 is affected.
Yes. CVE-2026-53541 is fixed in 0.0.0-20260531214440-ebffd9f040f7. Upgrade to this version or later.
Whether CVE-2026-53541 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade github.com/OliveTin/OliveTin to 0.0.0-20260531214440-ebffd9f040f7 or later.