iOSOperating system · Cisco
CVE-2015-4185
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 · uneditedThe TCL interpreter in Cisco IOS 15.2 does not properly maintain the vty state, which allows local users to gain privileges by starting a session very soon after a TCL script execution, aka Bug ID CSCuq24202.
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 confidenceThe TCL interpreter in Cisco IOS 15.2 fails to properly maintain vty (virtual terminal) state after TCL script execution. This state corruption allows a local user to gain elevated privileges by initiating a vty session immediately after a TCL script completes, potentially bypassing authentication controls.
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
= 15.2\(4\)m6= 15.2mCVSS 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
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:L/AC:M/Au:N/C:C/I:C/A:C
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 Cisco IOS versionRun 'show version' on the IOS CLI and locate the version string in the output (e.g., 'Version 15.2(4)m6')Affected if The version is 15.2(4)m6 or 15.2m exactly (these are the only affected versions listed)
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Confirm TCL interpreter availabilityRun 'tclsh' or attempt to enter TCL mode via the CLI to verify the TCL interpreter is present on the deviceAffected if TCL interpreter is accessible on the device (required for the vulnerability to be exploitable)
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Review recent vty session logsRun 'show logging | include VTY' or 'show users' to examine recent virtual terminal session establishment timestampsAffected if Vty sessions were initiated immediately after TCL script execution completes (within seconds)
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Check for privilege escalation anomaliesRun 'show privilege' after vty login and compare against expected privilege levels; review authen/author logs for unexpected privilege changesAffected if Sessions show higher privilege than expected or authentication bypass patterns are present
A user is affected only if running exactly Cisco iOS version 15.2(4)m6 or 15.2m, has TCL enabled, and observes vty sessions bypassing authentication immediately after TCL scripts execute.
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 the appropriate Cisco IOS update or patch for bug ID CSCuq24202. Until then, restrict local administrative access and monitor for suspicious session activity occurring immediately after TCL script execution.
Fix this in iOS
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-4185 — 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-2015-4185 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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