[Bug]: Regression in User-Based Server-Side Encryption Breaks WebDAV Clients

[MCterra10]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Since updating to NC 32, I have been experiencing an issue with WebDAV clients accessing files on my server, which is using server-side encryption with user passwords.

See the following curl request:

root@argus:/home/terra# curl -u terra:[CENSORED] http://localhost:8082/remote.php/dav/files/terra/paintr-comm.txt
<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns">
  <s:exception>OC\Encryption\Exceptions\DecryptionFailedException</s:exception>
  <s:message>Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.</s:message>
</d:error>
curl: (18) end of response with 2207 bytes missing

Note that the server sends the content length of the file, but then cuts off the request prematurely with this error message.

I get the same response when using my actual password or app passwords.

However, WebDAV clients that support cookies do not seem to have this problem; if a valid session cookie is provided, the download succeeds.

There are no issues with Nextcloud Desktop or Android apps.

I get this error in the Nextcloud logs:

{
  "reqId": "XC7yUgVyjR5g4Uv5ZusQ",
  "level": 3,
  "time": "2025-10-01T11:40:12+00:00",
  "remoteAddr": "::1",
  "user": "terra",
  "app": "webdav",
  "method": "GET",
  "url": "/remote.php/dav/files/terra/paintr-comm.txt",
  "message": "Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.",
  "userAgent": "curl/8.14.1",
  "version": "32.0.0.13",
  "exception": {
    "Exception": "OC\\Encryption\\Exceptions\\DecryptionFailedException",
    "Message": "Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.",
    "Code": 0,
    "Trace": [
      {
        "file": "/var/www/nextcloud/lib/private/Files/Stream/Encryption.php",
        "line": 461,
        "function": "decrypt",
        "class": "OCA\\Encryption\\Crypto\\Encryption",
        "type": "->",
        "args": [
          "*** sensitive parameters replaced ***"
        ]
      },
      {
        "file": "/var/www/nextcloud/lib/private/Files/Stream/Encryption.php",
        "line": 260,
        "function": "readCache",
        "class": "OC\\Files\\Stream\\Encryption",
        "type": "->"
      },
      {
        "function": "stream_read",
        "class": "OC\\Files\\Stream\\Encryption",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/icewind/streams/src/Wrapper.php",
        "line": 54,
        "function": "fread"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/icewind/streams/src/CallbackWrapper.php",
        "line": 94,
        "function": "stream_read",
        "class": "Icewind\\Streams\\Wrapper",
        "type": "->"
      },
      {
        "function": "stream_read",
        "class": "Icewind\\Streams\\CallbackWrapper",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/http/lib/Sapi.php",
        "line": 108,
        "function": "stream_copy_to_stream"
      },
      {
        "file": "/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php",
        "line": 490,
        "function": "sendResponse",
        "class": "Sabre\\HTTP\\Sapi",
        "type": "::"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php",
        "line": 211,
        "function": "invokeMethod",
        "class": "Sabre\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/lib/Server.php",
        "line": 424,
        "function": "start",
        "class": "OCA\\DAV\\Connector\\Sabre\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/apps/dav/appinfo/v2/remote.php",
        "line": 22,
        "function": "exec",
        "class": "OCA\\DAV\\Server",
        "type": "->"
      },
      {
        "file": "/var/www/nextcloud/remote.php",
        "line": 151,
        "args": [
          "/var/www/nextcloud/apps/dav/appinfo/v2/remote.php"
        ],
        "function": "require_once"
      }
    ],
    "File": "/var/www/nextcloud/apps/encryption/lib/Crypto/Encryption.php",
    "Line": 315,
    "Hint": "Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.",
    "message": "Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.",
    "exception": [],
    "CustomMessage": "Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you."
  },
  "id": "68dd15340e429"
}

Steps to reproduce

1. Update to NC 32
2. Enable server-side encryption with user passwords
3. Attempt to download file via WebDAV with basic auth
4. Observe the error.

Expected behavior

File should download successfully when the correct credentials are provided.

Nextcloud Server version

32

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.4

Web server

Nginx

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Upgraded to a MAJOR version (ex. 31 to 32)

Are you using the Nextcloud Server Encryption module?

Encryption is Enabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "argus.lan.austation.net",
            "nextcloud.mcterra.id.au",
            "uzsb7vyrol4gffhseeei25rofur7k4uznilyvp4qhdm2mrvzeszddqyd.onion"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "32.0.0.13",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "3306",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 0,
            "timeout": 0
        },
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "theme": "",
        "loglevel": 2,
        "default_phone_region": "AU",
        "maintenance_window_start": 3,
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "app_install_overwrite": [
            "end_to_end_encryption"
        ],
        "updater.release.channel": "stable",
        "preview_max_filesize_image": 200
    }
}

List of activated Apps

nabled:
  - activity: 5.0.0-dev.0
  - announcementcenter: 7.2.1
  - app_api: 32.0.0
  - bruteforcesettings: 5.0.0-dev.0
  - cloud_federation_api: 1.16.0
  - dashboard: 7.12.0
  - dav: 1.34.2
  - encryption: 2.20.0
  - federatedfilesharing: 1.22.0
  - files: 2.4.0
  - files_downloadlimit: 5.0.0-dev.0
  - files_pdfviewer: 5.0.0-dev.0
  - files_reminders: 1.5.0
  - files_sharing: 1.24.0
  - files_trashbin: 1.22.0
  - files_versions: 1.25.0
  - firstrunwizard: 5.0.0-dev.0
  - logreader: 5.0.0-dev.0
  - lookup_server_connector: 1.20.0
  - nextcloud_announcements: 4.0.0-dev.0
  - notifications: 5.0.0-dev.0
  - oauth2: 1.20.0
  - password_policy: 4.0.0-dev.0
  - photos: 5.0.0-dev.1
  - privacy: 4.0.0-dev.0
  - profile: 1.1.0
  - provisioning_api: 1.22.0
  - recommendations: 5.0.0-dev.0
  - related_resources: 3.0.0-dev.0
  - serverinfo: 4.0.0-dev.0
  - settings: 1.15.1
  - sharebymail: 1.22.0
  - survey_client: 4.0.0-dev.0
  - terms_of_service: 4.6.0
  - text: 6.0.0-dev.0
  - theming: 2.7.0
  - twofactor_backupcodes: 1.21.0
  - updatenotification: 1.22.0
  - viewer: 5.0.0-dev.0
  - webhook_listeners: 1.3.0
  - workflowengine: 2.14.0
Disabled:
  - admin_audit: 1.22.0
  - circles: 32.0.0 (installed 27.0.1)
  - comments: 1.22.0 (installed 1.17.0)
  - contactsinteraction: 1.13.1 (installed 1.8.0)
  - federation: 1.22.0 (installed 1.17.0)
  - files_external: 1.24.0
  - support: 4.0.0-dev.0 (installed 1.10.0)
  - suspicious_login: 10.0.0-dev.0
  - systemtags: 1.22.0 (installed 1.17.0)
  - twofactor_nextcloud_notification: 6.0.0-dev.0
  - twofactor_totp: 14.0.0
  - user_ldap: 1.23.0
  - user_status: 1.12.0 (installed 1.7.0)
  - weather_status: 1.12.0 (installed 1.7.0)

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

{"reqId":"XC7yUgVyjR5g4Uv5ZusQ","level":3,"time":"2025-10-01T11:40:12+00:00","remoteAddr":"::1","user":"terra","app":"webdav","method":"GET","url":"/remote.php/dav/files/terra/paintr-comm.txt","message":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","userAgent":"curl/8.14.1","version":"32.0.0.13","exception":{"Exception":"OC\\Encryption\\Exceptions\\DecryptionFailedException","Message":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","Code":0,"Trace":[{"file":"/var/www/nextcloud/lib/private/Files/Stream/Encryption.php","line":461,"function":"decrypt","class":"OCA\\Encryption\\Crypto\\Encryption","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/nextcloud/lib/private/Files/Stream/Encryption.php","line":260,"function":"readCache","class":"OC\\Files\\Stream\\Encryption","type":"->"},{"function":"stream_read","class":"OC\\Files\\Stream\\Encryption","type":"->"},{"file":"/var/www/nextcloud/3rdparty/icewind/streams/src/Wrapper.php","line":54,"function":"fread"},{"file":"/var/www/nextcloud/3rdparty/icewind/streams/src/CallbackWrapper.php","line":94,"function":"stream_read","class":"Icewind\\Streams\\Wrapper","type":"->"},{"function":"stream_read","class":"Icewind\\Streams\\CallbackWrapper","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/http/lib/Sapi.php","line":108,"function":"stream_copy_to_stream"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":490,"function":"sendResponse","class":"Sabre\\HTTP\\Sapi","type":"::"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":211,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Server.php","line":424,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/remote.php","line":22,"function":"exec","class":"OCA\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/remote.php","line":151,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/remote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/encryption/lib/Crypto/Encryption.php","Line":315,"Hint":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","message":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","exception":[],"CustomMessage":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you."},"id":"68dd16f8cd7b4"}
{"reqId":"XC7yUgVyjR5g4Uv5ZusQ","level":3,"time":"2025-10-01T11:40:12+00:00","remoteAddr":"::1","user":"terra","app":"no app in context","method":"GET","url":"/remote.php/dav/files/terra/paintr-comm.txt","message":"Uncaught exception","userAgent":"curl/8.14.1","version":"32.0.0.13","exception":{"Exception":"OC\\Encryption\\Exceptions\\DecryptionFailedException","Message":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","Code":0,"Trace":[{"file":"/var/www/nextcloud/lib/private/Files/Stream/Encryption.php","line":461,"function":"decrypt","class":"OCA\\Encryption\\Crypto\\Encryption","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/nextcloud/lib/private/Files/Stream/Encryption.php","line":260,"function":"readCache","class":"OC\\Files\\Stream\\Encryption","type":"->"},{"function":"stream_read","class":"OC\\Files\\Stream\\Encryption","type":"->"},{"file":"/var/www/nextcloud/3rdparty/icewind/streams/src/Wrapper.php","line":54,"function":"fread"},{"file":"/var/www/nextcloud/3rdparty/icewind/streams/src/CallbackWrapper.php","line":94,"function":"stream_read","class":"Icewind\\Streams\\Wrapper","type":"->"},{"function":"stream_read","class":"Icewind\\Streams\\CallbackWrapper","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/http/lib/Sapi.php","line":108,"function":"stream_copy_to_stream"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":490,"function":"sendResponse","class":"Sabre\\HTTP\\Sapi","type":"::"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":211,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Server.php","line":424,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/remote.php","line":22,"function":"exec","class":"OCA\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/remote.php","line":151,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/remote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/encryption/lib/Crypto/Encryption.php","Line":315,"Hint":"Cannot decrypt this file, probably this is a shared file. Please ask the file owner to reshare the file with you.","message":"Uncaught exception","exception":[],"CustomMessage":"Uncaught exception"},"id":"68dd16f8cd7a5"}

Additional info

Tested broken using cURL, KeePass2Android, and Bruno API dev tool, working using FX File Explorer (Android) - latter uses cookies as mentioned above (verified with wireshark).

[MCterra10]

This is a regression in commit b74c753 @come-nc .

Patching in a reversion of this (and 8330f14) has resolved the issue on my end.