peass-ng/PEASS-ng · error · ArgumentOutOfRangeException

Specified argument was out of the range of valid values. (Pa

Error message

Specified argument was out of the range of valid values. (Parameter 'index')

What it means

RunningTaskCollection's indexer walks the V1 running-task enumerator and throws ArgumentOutOfRangeException("index") when the supplied index exceeds the number of currently running tasks. Under the V1 API the collection length is unknown upfront, so out-of-range access is only detected during enumeration.

Source

Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/TaskCollection.cs:62

        /// <summary>Gets the specified running task from the collection.</summary>
        /// <param name="index">The index of the running task to be retrieved.</param>
        /// <returns>A <see cref="RunningTask"/> instance.</returns>
        public RunningTask this[int index]
        {
            get
            {
                if (v2Coll != null)
                {
                    var irt = v2Coll[++index];
                    return new RunningTask(svc, TaskService.GetTask(svc.v2TaskService, irt.Path), irt);
                }

                var i = 0;
                var v1Enum = new V1RunningTaskEnumerator(svc);
                while (v1Enum.MoveNext())
                    if (i++ == index)
                        return v1Enum.Current;
                throw new ArgumentOutOfRangeException(nameof(index));
            }
        }

        /// <summary>Releases all resources used by this class.</summary>
        public void Dispose()
        {
            if (v2Coll != null)
                Marshal.ReleaseComObject(v2Coll);
        }

        /// <summary>Gets an IEnumerator instance for this collection.</summary>
        /// <returns>An enumerator.</returns>
        public IEnumerator<RunningTask> GetEnumerator()
        {
            if (v2Coll != null)
                return new ComEnumerator<RunningTask, IRunningTask>(() => v2Coll.Count, (object o) => v2Coll[o], o =>
                {
                    IRegisteredTask task = null;

View on GitHub (pinned to 53fb989abc)

Solutions

Enumerate the collection with foreach instead of indexing
Compare against the live Count immediately before indexing, or use FirstOrDefault-style iteration
Re-fetch the collection after any wait/state change rather than reusing a stale reference
Catch ArgumentOutOfRangeException when the index is derived from external input

Example fix

// before
var task = runningTasks[i];
// after
var task = runningTasks.FirstOrDefault(t => /* match criteria */);
// or: foreach (var t in runningTasks) { ... }

Defensive patterns

Strategy: try-catch

Validate before calling

if (index >= 0 && index < runningTasks.Count) { var t = runningTasks[index]; }

Try / catch

try { var t = runningTasks[i]; } catch (ArgumentOutOfRangeException) { Log("Running task no longer active"); }

Prevention

Prefer foreach enumeration over positional indexing
Never cache counts across waits; the running set changes constantly
Validate external indexes against live Count immediately before use

When it happens

Trigger: Accessing RunningTaskCollection[index] where index >= the number of tasks currently running (V1 path at TaskCollection.cs:62), e.g. collection[5] when only 2 tasks are running; also when a task finishes between a Count check and the indexer call.

Common situations: Iterating a running-task list with a cached/stale count; racing with tasks completing; assuming the running set matches the registered-task set.

Related errors

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/c1c0eac677ee5e1c. Report an issue: GitHub.