dbcve.org
Ios XeOperating system · Cisco

CVE-2019-12658

HIGH · 7.5 CVSS v3.1 Published 2019-09-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability in the filesystem resource management code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to exhaust filesystem resources on an affected device and cause a denial of service (DoS) condition. The vulnerability is due to ineffective management of the underlying filesystem resources. An attacker could exploit this vulnerability by performing specific actions that result in messages being sent to specific operating system log files. A successful exploit could allow the attacker to exhaust available filesystem space on an affected device. This could cause the device to crash and reload, resulting in a DoS condition for clients whose network traffic is transiting the device. Upon reload of the device, the impacted filesystem space is cleared, and the device will return to normal operation. However, continued exploitation of this vulnerability could cause subsequent forced crashes and reloads, which could lead to an extended DoS condition.

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 confidence

A vulnerability in Cisco IOS XE Software's filesystem resource management allows an unauthenticated remote attacker to exhaust filesystem space by sending specific messages that get written to OS log files. The uncontrolled logging fills the filesystem, causing the device to crash and reload. While a reload clears the space, repeated exploitation leads to sustained DoS.

MitigationApply the relevant Cisco IOS XE software patch/update to remediate the filesystem resource management flaw. Consider implementing log rotation or size limits as a temporary mitigation if immediate patching is not feasible.

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
Ios XeOperating system
Affected:= 16.6.1= 16.8.1

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Cisco IOS XE platform
    Execute 'show version' command and look for 'IOS XE' in the output. This vulnerability only affects Cisco IOS XE devices, not classic IOS.
    Affected if Device does not run Cisco IOS XE software
  2. Check IOS XE version
    Execute 'show version' and locate the version number (e.g., 16.6.1, 16.8.1). Compare against the affected versions 16.6.1 and 16.8.1.
    Affected if Running version 16.6.1 or 16.8.1 exactly, or potentially other versions in the 16.6.x or 16.8.x family if they share the vulnerable code
  3. Verify remote access exposure
    Check if the device management interfaces (HTTP, HTTPS, SSH) are accessible from untrusted networks using 'show ip interface brief' and review access lists with 'show access-lists'.
    Affected if Management interfaces are exposed to untrusted networks without proper ACL restrictions
  4. Monitor filesystem utilization
    Execute 'show file systems' or 'dir' to check available disk space. Also check log size with 'show logging' and review log buffer allocation.
    Affected if Filesystem is near capacity or log files are growing abnormally large
  5. Review logging configuration
    Execute 'show logging' to examine logging settings, particularly buffered logging, file logging, and any syslog configurations that write to local storage.
    Affected if Logging to local filesystem is enabled without size limits or rotation configured

A user is affected if they run Cisco IOS XE versions 16.6.1 or 16.8.1 with management interfaces accessible to remote attackers and local filesystem logging enabled, as the vulnerability allows unauthenticated messages to fill log storage and cause repeated device reloads.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco IOS XE software patch/update to remediate the filesystem resource management flaw. Consider implementing log rotation or size limits as a temporary mitigation if immediate patching is not feasible.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-12658 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data