CVE-2017-17840
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 issue was discovered in Open-iSCSI through 2.0.875. A local attacker can cause the iscsiuio server to abort or potentially execute code by sending messages with incorrect lengths, which (due to lack of checking) can lead to buffer overflows, and result in aborts (with overflow checking enabled) or code execution. The process_iscsid_broadcast function in iscsiuio/src/unix/iscsid_ipc.c does not validate the payload length before a write operation.
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 confidenceOpen-iSCSI through 2.0.875 contains a buffer overflow vulnerability in the iscsiuio server's process_iscsid_broadcast function (iscsiuio/src/unix/iscsid_ipc.c). The function fails to validate payload length before a write operation, allowing a local attacker to send malformed messages with incorrect lengths that overflow buffers, potentially enabling code execution or causing service aborts.
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<= 2.0.875CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/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 if Open-iSCSI is installedRun 'dpkg -l open-iscsi' (Debian/Ubuntu) or 'rpm -qa | grep -i iscsi' (RHEL/CentOS) to list installed iscsi packagesAffected if No open-iscsi package is found, meaning Open-iSCSI is not installed and the system is not affected by this CVE
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Determine installed Open-iSCSI versionRun 'dpkg -s open-iscsi' (Debian/Ubuntu) or 'rpm -qi open-iscsi' (RHEL/CentOS) and note the Version fieldAffected if The installed version is 2.0.875 or lower, indicating the vulnerable version of Open-iSCSI is present
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Check if iscsiuio daemon is runningRun 'ps aux | grep iscsiuio' to see if the iscsiuio process is activeAffected if The iscsiuio daemon is running - this is the component containing the vulnerable process_iscsid_broadcast function
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Verify the iscsiuio IPC socket existsCheck for the iscsid IPC socket (commonly at /var/run/iscsiuiod or /var/run/iscsid.socket) using 'ls -la /var/run/ | grep -i iscsi'Affected if The IPC socket exists, confirming the iscsiuio server is operational and the vulnerable code path could be triggered
A system is affected if Open-iSCSI version 2.0.875 or lower is installed AND the iscsiuio daemon is running, enabling a local attacker to send malformed messages to the iscsiuio server IPC socket and trigger the buffer overflow in process_iscsid_broadcast.
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 dataApply vendor patches for CVE-2017-17840 which add proper payload length validation in the process_iscsid_broadcast function before performing write operations. If no patch available, implement bounds checking on the payload length field and validate against buffer sizes.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-17840 — 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-2017-17840 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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