CVE-2023-34758
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 · uneditedSliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.
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 confidenceSliver implant v1.5.x through v1.5.39 contains an improper cryptographic implementation in its C2 communication protocol, allowing man-in-the-middle attackers to intercept and craft responses between implants and the C2 server. This suggests a failure in certificate validation, certificate pinning, or mutual authentication mechanisms.
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>= 1.5.0, < 1.5.40CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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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Check Sliver server versionRun 'sliver-server --version' or 'sliver-client --version' to determine the installed Sliver versionAffected if Version is 1.5.0 or higher but lower than 1.5.40
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Identify active C2 listenersUse 'sliver-server' or 'sliver-client' and run 'listeners' or 'jobs' command to see if any C2 listeners are runningAffected if Any active listeners exist on an affected version
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Verify listener configuration uses mTLS or secured transportRun 'listener info <listener-name>' to inspect the listener configuration for transport security settingsAffected if Listener uses HTTP/HTTPS transport without mutual TLS or certificate pinning enabled
You are affected if you are running Sliver server version 1.5.0 through 1.5.39 with active C2 listeners that lack proper certificate validation or mutual authentication in their transport configuration.
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 · scoped1.5.40
Upgrade Sliver to version 1.5.40 or later, which contains the cryptographic fix. After upgrading, regenerate all active implants and listener configurations to ensure secure communication channels.
Sliver 1.5.40
- Backup your existing Sliver configuration, implants, and any critical data
- Verify current Sliver version is within the vulnerable range (>= 1.5.0, < 1.5.40)
- Download Sliver version 1.5.40 from the official GitHub releases (github.com/BishopFox/sliver)
- Stop any running Sliver server instances
- Install or upgrade to Sliver 1.5.40 using standard installation methods (e.g., 'sliver' binary replacement or package manager update)
- Restart the Sliver server with the new version
- Verify the upgraded version is 1.5.40 or later using 'version' command
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-34758 — 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-2023-34758 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
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