dotnet/wpf · error · FileFormatException

SR.CorruptedData

Error message

SR.CorruptedData

What it means

CertificatePart.GetCertificate throws this FileFormatException with SR.CorruptedData when the X.509 certificate bytes read from the certificate part cannot be constructed into an X509Certificate2 — the part's data is corrupt or not a valid certificate stream.

Solutions

1. Verify the certificate part data in the package is not corrupted or oversized
2. Re-export the digital signature/certificate part with valid X.509 data
3. Catch FileFormatException when opening untrusted XPS packages and surface a corruption error

When it happens

Trigger: Thrown at src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/IO/Packaging/Certificate.cs:99 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/ccce6b43f676bd09. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/WindowsBase/MS/Internal/IO/Packaging/Certificate.cs:99

        //------------------------------------------------------
        /// <summary>
        /// Certificate to associate with this Certificate Part
        /// </summary>
        /// <value></value>
        /// <exception cref="FileFormatException">stream is too large</exception>
        internal X509Certificate2 GetCertificate()
        {
            // lazy init
            if (_certificate == null)
            {
                // obtain from the part
                using (Stream s = _part.GetStream())
                {
                    if (s.Length > 0)
                    {
                        // throw if stream is beyond any reasonable length
                        if (s.Length > _maximumCertificateStreamLength)
                            throw new FileFormatException(SR.CorruptedData);

                        // X509Certificate constructor desires a byte array
                        Byte[] byteArray = new Byte[s.Length];
                        PackagingUtilities.ReliableRead(s, byteArray, 0, (int)s.Length);
                        _certificate = X509CertificateLoader.LoadCertificate(byteArray);
                    }
                }
            }
            return _certificate;
        }

        internal void SetCertificate(X509Certificate2 certificate)
        {
            ArgumentNullException.ThrowIfNull(certificate);

            _certificate = certificate;

            // persist to the part

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