CVE-2026-3091
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 · uneditedAn uncontrolled search path element vulnerability in Synology Presto Client before 2.1.3-0672 allows local users to read or write arbitrary files and conduct denial-of-service during installation by placing a malicious DLL in advance in the same directory as the installer.
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 · high confidenceSynology Presto Client before version 2.1.3-0672 contains an uncontrolled search path element vulnerability where the installer loads DLL files from its current directory without proper path validation. A local attacker can place a malicious DLL in the same directory as the installer prior to installation, causing the installer to execute the arbitrary code and achieve local privilege escalation to read/write arbitrary files or cause denial-of-service.
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< 2.1.3-0672CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Locate Synology Presto Client installationCheck for Synology Presto Client in typical installation directories such as C:\Program Files\Synology\Synology Presto Client or C:\Program Files (x86)\Synology\Synology Presto Client. Also check Add/Remove Programs or Programs and Features for the installed application.Affected if Synology Presto Client is installed on the system
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Identify installed versionOpen Control Panel > Programs and Features, find Synology Presto Client in the list, and note the version number displayed. Alternatively, right-click the main executable (typically presto.exe or Presto.exe) in the installation folder, select Properties, and check the Details tab for the File Version.Affected if The version shown is lower than 2.1.3-0672 (for example, 2.1.2-xxxx or any version number that precedes 2.1.3-0672)
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Confirm vulnerability conditionCompare your identified version against the affected range: any version before 2.1.3-0672 is vulnerable. Versions 2.1.3-0672 and later are not affected.Affected if The installed version falls below 2.1.3-0672
A system is affected if Synology Presto Client is installed with a version number lower than 2.1.3-0672, making it vulnerable to DLL hijacking during installation.
Generated from the published advisory. Verify against your own configuration.
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 · scoped2.1.3-0672
Upgrade Synology Presto Client to version 2.1.3-0672 or later, which should implement secure DLL loading using full paths or trusted directory validation. Additionally, ensure installation directories are not writable by untrusted users.
2.1.3-0672 or later
- Obtain the fixed version of Synology Presto Client (version 2.1.3-0672 or later) from the official Synology website at www.synology.com
- Verify the integrity of the downloaded installer using checksums if provided by Synology
- Close any running instances of Presto Client
- Execute the installer with appropriate administrator privileges
- Follow the installation wizard prompts to complete the upgrade
- Restart the system if prompted to ensure the new DLL search path is properly loaded
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-3091 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-3091 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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