NVD / CVE Program· CNA cisco

CVE-2019-12658: Cisco IOS XE Software Filesystem Exhaustion Denial of Service Vulnerability

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 1.9% (FIRST EPSS); higher than 80.2% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit No fix recorded

BDU:2019-03430

Published: Sep 25, 2019
Updated: Jun 16, 2026
EPSS: 1.9% · 80th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 1 / 30 · 1.9%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 7.5
CNA · cisco: 8.6; 1.1 point gap

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
cisco	ios xe	cpe:2.3:o:cisco:ios_xe
cisco	1100 integrated services r	cpe:2.3:h:cisco:1100_integrated_services_r
cisco	4221 integrated services r	cpe:2.3:h:cisco:4221_integrated_services_r
cisco	4321 integrated services r	cpe:2.3:h:cisco:4321_integrated_services_r
cisco	4331 integrated services r	cpe:2.3:h:cisco:4331_integrated_services_r
cisco	4351 integrated services r	cpe:2.3:h:cisco:4351_integrated_services_r
cisco	4431 integrated services r	cpe:2.3:h:cisco:4431_integrated_services_r
cisco	4451-x integrated services r	cpe:2.3:h:cisco:4451-x_integrated_services_r
cisco	asr 1000	cpe:2.3:h:cisco:asr_1000
cisco	asr 1001-hx r	cpe:2.3:h:cisco:asr_1001-hx_r
cisco	asr 1001-x r	cpe:2.3:h:cisco:asr_1001-x_r
cisco	asr 1002-hx r	cpe:2.3:h:cisco:asr_1002-hx_r

and 139 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

cisco ios xe16.6.1
cisco ios xe16.8.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

Cisco Cisco IOS XE Software 16.1.1
- unspecified and later · before n/aaffected

Same product

cisco: all records

Other highest-scoring records for the same primary product.

CVE-2023-20198Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software.KEV
100Now
CVE-2023-20273A vulnerability in the web UI feature of Cisco IOS XE Software could allow an authenticated, remote attacker to inject commands with the priKEV
86Now
CVE-2018-0151A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, reKEV
73This week

Published before and after this one in the same product

← EarlierCVE-2019-12654Sep 25, 2019 · Cisco IOS and IOS XE Software Session Initiation Protocol Denial of Service Vulnerability
31Monitor
← EarlierCVE-2019-12657Sep 25, 2019 · Cisco IOS XE Software Unified Threat Defense Denial of Service Vulnerability
31Monitor
Later →CVE-2019-12659Sep 25, 2019 · Cisco IOS XE Software HTTP Server Denial of Service Vulnerability
31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-iosxe-fsdos

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records