peass-ng/PEASS-ng · error · ArgumentException

too few objects in input vector

Error message

too few objects in input vector

What it means

GetObjFromVector extracts the Asn1Object at a given index from an Asn1EncodableVector while DerExternal parses its fields. If the vector has no element at that index (Count <= index), the External structure is missing a required field, so ArgumentException is thrown.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/DerExternal.cs:187

			}
		}

		public Asn1Object ExternalContent
		{
			get { return externalContent; }
			set { this.externalContent = value; }
		}

		public DerInteger IndirectReference
		{
			get { return indirectReference; }
			set { this.indirectReference = value; }
		}

		private static Asn1Object GetObjFromVector(Asn1EncodableVector v, int index)
		{
			if (v.Count <= index)
				throw new ArgumentException("too few objects in input vector", "v");

			return v[index].ToAsn1Object();
		}

		private static void WriteEncodable(MemoryStream ms, Asn1Encodable e)
		{
			if (e != null)
			{
				byte[] bs = e.GetDerEncoded();
				ms.Write(bs, 0, bs.Length);
			}
		}
	}
}

View on GitHub (pinned to 53fb989abc)

Solutions

1. Check vector.Count > offset before calling the DerExternal vector constructor
2. Re-parse the source data — too few objects means the encoding is truncated or malformed
3. Ensure the offset argument points at the first External field, not beyond the vector

Example fix

// before
var ext = new DerExternal(vector, offset);
// after
if (vector.Count <= offset)
    throw new FormatException("External vector truncated");
var ext = new DerExternal(vector, offset);

if (vector == null || vector.Count <= offset)
    throw new FormatException("Vector too short to contain an External");
var ext = new DerExternal(vector, offset);

static bool HasEnoughElements(Asn1EncodableVector v, int index) => v != null && v.Count > index;

try { var ext = new DerExternal(vector, offset); }
catch (ArgumentException ex) when (ex.Message.Contains("too few objects")) {
    // truncated or misaligned External vector
}

When it happens

Trigger: Constructing DerExternal(Asn1EncodableVector, int) where the vector is too short to supply the expected fields at the starting offset — e.g. an empty vector, or offset >= vector.Count.

Common situations: Passing a truncated or empty vector to the DerExternal vector constructor; parsing truncated BER streams where optional/required External fields were dropped; using the wrong offset so it points past the end.

Related errors

• ENUMERATED has zero length
• input vector too large
• No tagged object found in vector. Structure doesn't seem to
• malformed object
• must be in the range 0 to 7

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/35c1deb05fd839a0. Report an issue: GitHub.