Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability
Cisco · Cisco NX-OS Software
7.7HighCVSS 3.1
Recommended action
Within 7 days
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2019-10522
No EUVD known-exploited evidence
ENISA has published the identifier mapping but no EUVD description has been stored yet.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Fix not verified
01
What, why and how
A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH process to fail to delete upon termination. This can lead to a build-up of VSH processes that overtime can deplete system memory. When there is no system memory available, this can cause unexpected system behaviors and crashes. The vulnerability is due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly performing a remote management connection to the device and terminating the connection in an unexpected manner. A successful exploit could allow the attacker to cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition. The attacker must have valid user credentials to log in to the device using the remote management connection.
What
A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH process to fail to delete upon termination. This can lead to a build-up of VSH processes that overtime can deplete system memory. When there is no system memory available, this can cause unexpected system behaviors and crashes. The vulnerability is due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly performing a remote management connection to the device and terminating the connection in an unexpected manner. A successful exploit could allow the attacker to cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition. The attacker must have valid user credentials to log in to the device using the remote management connection.
Why
The product does not properly control the allocation and maintenance of a limited resource.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.
What
A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH process to fail to delete upon termination. This can lead to a build-up of VSH processes that overtime can deplete system memory. When there is no system memory available, this can cause unexpected system behaviors and crashes. The vulnerability is due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly performing a remote management connection to the device and terminating the connection in an unexpected manner. A successful exploit could allow the attacker to cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition. The attacker must have valid user credentials to log in to the device using the remote management connection.
Why
The product does not properly control the allocation and maintenance of a limited resource.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.None recorded
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
Likely attack path
a network path → Uncontrolled Resource Consumption → disrupt the affected service
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkDenial of serviceCWE-400
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
unspecified < 8.4(1)
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 28 Aug 2019 · Last source change 21 Nov 2024, 19:15 UTC · CWE-400 · Uncontrolled Resource Consumption
CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-09-01
European sourceENISA EUVD · EUVD-2019-10522
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment
Core structured fields are present and their contributing authorities are shown above.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2019-1965: Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability | BlackTree