CVE-2021-26733
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 · uneditedA broken access control vulnerability in the FirstReset_handler_func function of spx_restservice allows an attacker to arbitrarily send reboot commands to the BMC, causing a Denial-of-Service (DoS) condition. This issue affects: Lanner Inc IAC-AST2500A standard firmware version 1.10.0.
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 confidenceA broken access control vulnerability in the FirstReset_handler_func function of spx_restservice allows unauthenticated or improperly authorized attackers to send arbitrary reboot commands to the Baseboard Management Controller (BMC), causing a complete Denial-of-Service condition. This affects Lanner IAC-AST2500A firmware version 1.10.0.
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= 1.10.0CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify the BMC hardware modelAccess the BMC web interface or use IPMI commands (ipmitool -I lanplus -H <BMC_IP> -U <user> mc info) to confirm the hardware is Lanner IAC-AST2500AAffected if The hardware model is Lanner IAC-AST2500A
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Check the BMC firmware versionUse IPMI command 'ipmitool -I lanplus -H <BMC_IP> -U <user> mc info' or check the firmware version via the BMC web interface under Firmware/Version informationAffected if The firmware version is exactly 1.10.0
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Verify spx_restservice is accessibleCheck if port 443 or the BMC REST API endpoint is reachable from the network using 'curl -k https://<BMC_IP>/api' or a port scan for HTTP/HTTPS services on the BMCAffected if The BMC REST API service (spx_restservice) is exposed on the network and accepts requests
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Confirm FirstReset API endpoint existsAttempt to access the FirstReset handler endpoint via the REST API (such as /api/reset or similar endpoint exposing FirstReset_handler_func), or examine the BMC's available API endpointsAffected if The FirstReset_handler_func endpoint is available and responds to requests without proper authorization checks
You are affected if you have a Lanner IAC-AST2500A BMC running firmware version 1.10.0 with the spx_restservice exposed and the FirstReset API endpoint accessible without authentication.
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 dataUpdate the firmware to a patched version that properly implements access control checks in the FirstReset_handler_func function, restricting reboot commands to authorized users only.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 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 $3,168.
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Free · runs locallyCheck whether your project pulls in CVE-2021-26733 — 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-2021-26733 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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- Version or environment caveats, and links to real fixes
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