peass-ng/PEASS-ng · error · EndOfStreamException

EOF found when length expected

Error message

EOF found when length expected

What it means

An EndOfStreamException from ReadLength: the first byte read for the length octets of a TLV was -1, i.e. the stream ended right after the tag with no length field present. It indicates a truncated or prematurely terminated ASN.1 stream.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/Asn1InputStream.cs:277

                    tagNo |= (b & 0x7f);
                    tagNo <<= 7;
                    b = s.ReadByte();
                }

                if (b < 0)
                    throw new EndOfStreamException("EOF found inside tag value.");

                tagNo |= (b & 0x7f);
            }

            return tagNo;
        }

        internal static int ReadLength(Stream s, int limit, bool isParsing)
        {
            int length = s.ReadByte();
            if (length < 0)
                throw new EndOfStreamException("EOF found when length expected");

            if (length == 0x80)
                return -1;      // indefinite-length encoding

            if (length > 127)
            {
                int size = length & 0x7f;

                // Note: The invalid long form "0xff" (see X.690 8.1.3.5c) will be caught here
                if (size > 4)
                    throw new IOException("DER length more than 4 bytes: " + size);

                length = 0;
                for (int i = 0; i < size; i++)
                {
                    int next = s.ReadByte();

                    if (next < 0)

View on GitHub (pinned to 53fb989abc)

Solutions

1. Verify the input is complete and well-formed ASN.1 before constructing Asn1InputStream
2. Fix upstream truncation (network cutoff, partial file write, bad Base64 decode)
3. Catch EndOfStreamException where partial/malformed input is expected and report it as malformed data

When it happens

Trigger: Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/asn1/Asn1InputStream.cs:277 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/babd8c3b09d0b999. Report an issue: GitHub.