peass-ng/PEASS-ng · error · ArithmeticException

The flag value has more than a single bit set.

Error message

The flag value has more than a single bit set.

What it means

BitPosition<T> throws InvalidEnumArgumentException stating more than a single bit is set when the supplied flags value has multiple bits (e.g. 0x3). The method is only meaningful for a single-bit flag, so a multi-bit combination is the invalid input; the check runs after CheckIsEnum<T>(true) confirms T is a [Flags] enum.

Source

Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/EnumUtil.cs:41

            {
                var allFlags = 0L;
                foreach (T flag in Enum.GetValues(typeof(T)))
                    allFlags |= Convert.ToInt64(flag);
                if ((allFlags & Convert.ToInt64(value)) != 0L)
                    return;
            }
            else if (Enum.IsDefined(typeof(T), value))
                return;
            throw new InvalidEnumArgumentException(argName ?? "value", Convert.ToInt32(value), typeof(T));
        }

        public static byte BitPosition<T>(this T flags) where T : struct, IConvertible
        {
            CheckIsEnum<T>(true);
            var flagValue = Convert.ToInt64(flags);
            if (flagValue == 0) throw new ArgumentException("The flag value is zero and has no bit position.");
            var r = Math.Log(flagValue, 2);
            if (r % 1 > 0) throw new ArithmeticException("The flag value has more than a single bit set.");
            return Convert.ToByte(r);
        }

        public static bool IsFlagSet<T>(this T flags, T flag) where T : struct, IConvertible
        {
            CheckIsEnum<T>(true);
            var flagValue = Convert.ToInt64(flag);
            return (Convert.ToInt64(flags) & flagValue) == flagValue;
        }

        public static bool IsValidFlagValue<T>(this T flags) where T : struct, IConvertible
        {
            CheckIsEnum<T>(true);
            var found = 0L;
            foreach (T flag in Enum.GetValues(typeof(T)))
            {
                if (flags.IsFlagSet(flag))
                    found |= Convert.ToInt64(flag);

View on GitHub (pinned to 53fb989abc)

Solutions

1. Ensure the value has exactly one bit set (e.g. value != 0 && (value & (value - 1)) == 0) before calling.
2. Iterate over individual flags and call BitPosition per flag instead of on combinations.
3. Catch InvalidEnumArgumentException and decompose the multi-bit value manually if combinations are expected.

When it happens

Trigger: Thrown at winPEAS/winPEASexe/winPEAS/TaskScheduler/EnumUtil.cs:41 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/223abe0bd0bbcdaa. Report an issue: GitHub.