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Mail ServerApplication · Synology

CVE-2025-2848

MEDIUM · 6.3 CVSS v3.1 Published 2025-12-04
Fix available
A fix is available. Upgrade to 1.7.6-10676 / 1.7.6-20676 or later.
See remediation →
69/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in Synology Mail Server allows remote authenticated attackers to read and write non-sensitive settings, and disable some non-critical functions.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Synology Mail Server contains a vulnerability allowing remote authenticated attackers to read and write non-sensitive settings and disable certain non-critical functions. The attack requires valid authentication credentials, suggesting the vulnerability stems from improper authorization checks on specific configuration endpoints rather than a complete authentication bypass.

MitigationRestrict access to Synology Mail Server management interfaces to trusted networks or users only. Apply any available vendor patches. Monitor for unauthorized configuration changes.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Mail ServerApplication
Affected:< 1.7.6-10676< 1.7.6-20676

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Synology Mail Server installation
    Access Synology DSM and navigate to Package Center to verify Synology Mail Server package is installed, or run 'pkglist' via SSH to list installed packages
    Affected if Synology Mail Server is not installed then the CVE does not apply
  2. Identify installed version
    In DSM Package Center, click on Synology Mail Server and view the version information, or query via command line: 'cat /var/packages/MailServer/package.info' or equivalent package metadata
    Affected if Unable to determine version prevents accurate assessment
  3. Compare version against affected ranges
    Compare your installed version to the affected ranges: versions below 1.7.6-10676 and versions below 1.7.6-20676 are vulnerable
    Affected if Installed version is lower than 1.7.6-10676 or 1.7.6-20676
  4. Assess management interface exposure
    Check network access settings for Synology Mail Server management interface in DSM Control Panel > Security > Firewall or review reverse proxy configurations
    Affected if Management interface is exposed to untrusted networks (internet or non-admin users)
  5. Review for unauthorized configuration changes
    Check Synology Mail Server configuration logs or audit logs for any unexpected changes to settings, particularly changes to non-critical function states
    Affected if Unexpected configuration modifications are present that were not made by authorized administrators

Environment is affected if Synology Mail Server version is below 1.7.6-10676 (or 1.7.6-20676 depending on build) and the management interface is network-accessible to authenticated users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.7.6-10676 / 1.7.6-20676 or later
Fixed in 1.7.6-106761.7.6-20676
Interim mitigation

Restrict access to Synology Mail Server management interfaces to trusted networks or users only. Apply any available vendor patches. Monitor for unauthorized configuration changes.

Recommended fix High confidence

1.7.6-10676 or 1.7.6-20676 (or later)

  1. Log into Synology DiskStation Manager (DSM) as an administrator
  2. Open Package Center and locate Synology Mail Server in the installed package list
  3. Check the current version of Synology Mail Server to confirm it is below 1.7.6-10676 or 1.7.6-20676
  4. In Package Center, click on Synology Mail Server and select 'Update' to install the latest available version
  5. Alternatively, manually download the updated package from Synology's download center if automatic updates are not available
  6. After updating, verify the version has changed to 1.7.6-10676 or higher (or 1.7.6-20676 or higher for the specific release line)

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mail Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-2848 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data