CVE-2025-42921
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 · uneditedIn JetBrains Toolbox App before 2.6 host key verification was missing in SSH plugin
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 confidenceThe JetBrains Toolbox App versions prior to 2.6 lacked host key verification in the SSH plugin, allowing potential Man-In-The-Middle attacks where an attacker could intercept SSH connections by impersonating the target server.
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< 2.6CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
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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Verify JetBrains Toolbox is installedCheck if JetBrains Toolbox App is present on the system by looking for the application in your installed programs or running processesAffected if JetBrains Toolbox is not found on the system - not affected
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Determine installed version of JetBrains ToolboxOpen JetBrains Toolbox, click on the settings icon, and view the version number displayed in the About or version sectionAffected if Unable to determine version - further investigation needed
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Compare version against affected rangeCheck if the installed version is less than 2.6 (for example, 2.5.x, 2.4.x, etc.)Affected if Version is 2.6 or later - not affected by this CVE; version is below 2.6 - potentially affected if SSH plugin is used
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Confirm SSH plugin is in useCheck if the SSH plugin feature within JetBrains Toolbox is configured or has been used to establish SSH connectionsAffected if SSH plugin has never been used or configured - likely not affected; SSH plugin is actively used - affected by the missing host key verification
You are affected if JetBrains Toolbox version is below 2.6 AND you use or have used the SSH plugin to connect to remote servers.
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 · scoped2.6
Upgrade JetBrains Toolbox App to version 2.6 or later where host key verification is implemented. Until upgraded, avoid using the SSH plugin on untrusted networks.
2.6
- Open JetBrains Toolbox App
- Check the current version under the settings or tool listing
- If version is below 2.6, click the Update button next to Toolbox App
- Alternatively, download the latest version from the official JetBrains website
- Restart Toolbox App after updating to ensure the SSH plugin with host key verification is applied
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,456.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-42921 — 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-2025-42921 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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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.
- 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