Failed to add nzb with " (or other non-ASCII charachters) in name

[H3n-42]

Summary

Listenarr fails to send NZB files to SABnzbd when the NZB filename contains double quotes and non-ASCII characters, due to a .NET ContentDispositionHeaderValue.EncodeAndQuoteMime ArgumentException on the multipart Content-Disposition header.

Environment

• Listenarr version: 1.2.2
• Install type: Docker
• SABnzbd version: 4.5.5

Steps to Reproduce

1. Configure SABnzbd as a download client in Listenarr.
2. Grab an NZB with a subject like:
   (01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB from DrunkenSlug (Prowlarr)

Example ASIN B0CN72SGM6
Example ISBN 9783844933482

3. Attempt to send the prepared NZB to SABnzbd from Listenarr.

Actual Behavior

Listenarr throws:

listenarr  | 2026-08-10 12:15:52.421 +00:00 [INF] [Listenarr.Api.Features.Downloads.DownloadController] === SendToDownloadClient RECEIVED REQUEST ===
listenarr  | 2026-08-10 12:15:52.422 +00:00 [INF] [Listenarr.Api.Features.Downloads.DownloadController] Title: (01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB
listenarr  | 2026-08-10 12:15:52.422 +00:00 [INF] [Listenarr.Api.Features.Downloads.DownloadController] Protocol: Usenet
listenarr  | 2026-08-10 12:15:52.422 +00:00 [INF] [Listenarr.Api.Features.Downloads.DownloadController] Source: DrunkenSlug (Prowlarr)
listenarr  | 2026-08-10 12:15:52.422 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Preparing trusted download '(01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB' using protocol Usenet, AudiobookId: 1
listenarr  | 2026-08-10 12:15:52.728 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Processing as Usenet after server-side validation for '(01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB'
listenarr  | 2026-08-10 12:15:52.728 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadClientSelector] Looking for NZB client. Found 1 enabled download clients: SABnzbd (sabnzbd)
listenarr  | 2026-08-10 12:15:52.728 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadClientSelector] Selected NZB client: SABnzbd (sabnzbd)
listenarr  | 2026-08-10 12:15:52.728 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Auto-selected download client 1786306585203-ebswkjv23 for NZB
listenarr  | 2026-08-10 12:15:52.729 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Sending to sabnzbd download client: SABnzbd
listenarr  | 2026-08-10 12:15:52.738 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Created download record in database: 5ef8e3f2-ca86-4018-bd71-365a4b9e140c for '(01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB'
listenarr  | 2026-08-10 12:15:52.738 +00:00 [INF] [Listenarr.Infrastructure.DownloadClients.Sabnzbd.SabnzbdAdapter] Sending prepared NZB to SABnzbd: (01/21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB from DrunkenSlug (Prowlarr)
listenarr  | 2026-08-10 12:15:52.739 +00:00 [ERR] [Listenarr.Infrastructure.DownloadClients.Sabnzbd.SabnzbdAdapter] Failed to send NZB to SABnzbd
listenarr  | System.ArgumentException: The format of value '(01_21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB.nzb' is invalid.
listenarr  |    at System.Net.Http.Headers.ContentDispositionHeaderValue.EncodeAndQuoteMime(String input)
listenarr  |    at System.Net.Http.Headers.ContentDispositionHeaderValue.SetName(String parameter, String value)
listenarr  |    at System.Net.Http.MultipartFormDataContent.AddInternal(HttpContent content, String name, String fileName)
listenarr  |    at Listenarr.Infrastructure.DownloadClients.Sabnzbd.SabnzbdAddWorkflow.AddAsync(DownloadClientConfiguration client, PreparedDownloadSubmission submission, CancellationToken ct) in /home/runner/work/Listenarr/Listenarr/listenarr.infrastructure/DownloadClients/Sabnzbd/SabnzbdAddWorkflow.cs:line 48
listenarr  | 2026-08-10 12:15:52.745 +00:00 [INF] [Listenarr.Application.Downloads.Submission.DownloadService] Removed provisional download 5ef8e3f2-ca86-4018-bd71-365a4b9e140c after client submission failed
listenarr  | 2026-08-10 12:15:52.745 +00:00 [WRN] [Listenarr.Api.Features.Downloads.DownloadController] Download client submission failed
listenarr  | Listenarr.Application.Common.DownloadClientSubmissionException: Failed to send the torrent to the download client.
listenarr  |  ---> System.ArgumentException: The format of value '(01_21) - Description - "Rebecca Yarros - Flammengeküsst 02 - Iron Flame - Flammengeküsst (Ungekürzt).par2" - 1,99 GB.nzb' is invalid.
listenarr  |    at System.Net.Http.Headers.ContentDispositionHeaderValue.EncodeAndQuoteMime(String input)
listenarr  |    at System.Net.Http.Headers.ContentDispositionHeaderValue.SetName(String parameter, String value)
listenarr  |    at System.Net.Http.MultipartFormDataContent.AddInternal(HttpContent content, String name, String fileName)
listenarr  |    at Listenarr.Infrastructure.DownloadClients.Sabnzbd.SabnzbdAddWorkflow.AddAsync(DownloadClientConfiguration client, PreparedDownloadSubmission submission, CancellationToken ct) in /home/runner/work/Listenarr/Listenarr/listenarr.infrastructure/DownloadClients/Sabnzbd/SabnzbdAddWorkflow.cs:line 48
listenarr  |    at Listenarr.Application.Downloads.Common.DownloadClientGateway.AddAsync(DownloadClientConfiguration client, PreparedDownloadSubmission submission, CancellationToken ct) in /home/runner/work/Listenarr/Listenarr/listenarr.application/Downloads/Common/DownloadClientGateway.cs:line 80
listenarr  |    at Listenarr.Application.Downloads.Submission.DownloadService.SendToDownloadClientAsync(TrustedDownloadCandidate candidate, String downloadClientId, Nullable`1 audiobookId) in /home/runner/work/Listenarr/Listenarr/listenarr.application/Downloads/Submission/DownloadService.cs:line 337
listenarr  |    --- End of inner exception stack trace ---
listenarr  |    at Listenarr.Application.Downloads.Submission.DownloadService.SendToDownloadClientAsync(TrustedDownloadCandidate candidate, String downloadClientId, Nullable`1 audiobookId) in /home/runner/work/Listenarr/Listenarr/listenarr.application/Downloads/Submission/DownloadService.cs:line 357
listenarr  |    at Listenarr.Api.Features.Downloads.DownloadController.SendToDownloadClient(SendDownloadRequest request) in /home/runner/work/Listenarr/Listenarr/listenarr.api/Features/Downloads/DownloadController.cs:line 90

The request to SABnzbd is never sent; the provisional download is removed.

Possible fix

Sanitize the filename (e.g. strip or use known metadata as replacement)