FortisandboxApplication · Fortinet
CVE-2021-26098
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 instance of small space of random values in the RPC API of FortiSandbox before 4.0.0 may allow an attacker in possession of a few information pieces about the state of the device to possibly predict valid session IDs.
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 confidenceFortiSandbox versions before 4.0.0 use an insufficiently small space of random values when generating session IDs in their RPC API. An attacker who obtains partial information about the device state can leverage this limited entropy to predict valid session IDs, potentially hijacking legitimate sessions.
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
FortisandboxApplication
<= 3.1.4>= 3.2.0, < 3.2.3CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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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Confirm FortiSandbox is deployedCheck for FortiSandbox appliance or VM in your environment by reviewing installed software, VM inventory, or network device lists. Look for device hostname or service named 'FortiSandbox' or 'fortisandbox'.Affected if FortiSandbox is present in the environment
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Identify installed FortiSandbox versionLog into the FortiSandbox CLI or GUI and navigate to System > FortiGuard or use command: 'get system status' in CLI. This displays the firmware version.Affected if Version is 3.1.4 or lower, OR version is 3.2.0 through 3.2.2 (any version before 3.2.3 or 4.0.0)
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Check if RPC API is enabledIn FortiSandbox GUI, go to System > Administration > Administrators or use CLI command: 'show system global' to review RPC settings. Look for 'rpc' or 'rpc-service' configuration.Affected if RPC API service is enabled and accessible from network segments used by the check
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Verify RPC service accessibilityFrom an external host, attempt to reach the RPC interface on port 514 or 5140 (typical FortiSandbox ports) or check firewall rules allowing RPC access. Review access list in System > Network > Interface settings.Affected if RPC API port is open to untrusted networks or internet-facing interfaces
You are affected if FortiSandbox is running version 3.1.4 or lower, or version 3.2.0 through 3.2.2, AND the RPC API is enabled and accessible from where session prediction could occur.
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.
From vendor data3.2.3
Upgrade FortiSandbox to version 4.0.0 or later to obtain properly randomized session IDs with adequate entropy. If immediate upgrade is not feasible, consider restricting RPC API access to trusted networks or implementing additional authentication layers.
Fix this in Fortisandbox
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26098 — 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-2021-26098 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
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