iOSOperating system · Cisco
CVE-2018-15376
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 vulnerability in the embedded test subsystem of Cisco IOS Software for Cisco 800 Series Industrial Integrated Services Routers could allow an authenticated, local attacker to write arbitrary values to arbitrary locations in the memory space of an affected device. The vulnerability is due to the presence of certain test commands that were intended to be available only in internal development builds of the affected software. An attacker could exploit this vulnerability by using these commands on an affected device. A successful exploit could allow the attacker to write arbitrary values to arbitrary locations in the memory space of the affected device.
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 confidenceA vulnerability in the embedded test subsystem of Cisco IOS Software for Cisco 800 Series Industrial Integrated Services Routers allows an authenticated local attacker to write arbitrary values to arbitrary memory locations due to debug/test commands that were inadvertently included in production firmware builds.
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
iOSOperating system
= 15.5\(2.21\)t= 15.6\(3\)mCVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:H/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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Identify device modelExecute 'show version' or 'show inventory' to confirm the device is a Cisco 800 Series Industrial Integrated Services RouterAffected if Device is not a Cisco 800 Series Industrial ISR (not affected)
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Check IOS versionExecute 'show version' and locate the firmware version string in the output (typically displayed as something like 'Version 15.5(2.21)t')Affected if Unable to retrieve version information from the device
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Compare version against affected releasesMatch the exact version number shown in 'show version' output against 15.5(2.21)t and 15.6(3)m - note these are exact version matches (equals, not ranges)Affected if Version equals exactly 15.5(2.21)t OR equals exactly 15.6(3)m
The device is affected only if it is a Cisco 800 Series Industrial ISR running exactly version 15.5(2.21)t or version 15.6(3)m.
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 Cisco's firmware patch when available. Until then, restrict physical and logical access to affected devices to trusted, authenticated personnel only.
Fix this in iOS
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 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 $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-15376 — 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-2018-15376 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
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