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CVE Record

CVE-2023-20240: Multiple vulnerabilities in Cisco Secure Client Software, formerly AnyConnect Secure Mobility Client, could...

Multiple vulnerabilities in Cisco Secure Client Software, formerly AnyConnect Secure Mobility Client, could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected system. These vulnerabilities are due to an out-of-bounds memory read from Cisco Secure Client Software. An attacker could exploit these vulnerabilities by logging in to an affected device at the same time that another user is accessing Cisco Secure Client on the same system, and then sending crafted packets to a port on that local host. A successful exploit could allow the attacker to crash the VPN Agent service, causing it to be unavailable to all users of the system. To exploit these vulnerabilities, the attacker must have valid credentials on a multi-user system.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-20240 can let a logged-in local user crash Cisco Secure Client's VPN Agent service on a shared system. The main business impact is VPN availability loss for all users on that machine, not data theft or privilege escalation based on the provided sources.

Executive priority

Treat as a moderate operational resilience issue. It is unlikely to justify emergency response by itself, but shared systems running affected Cisco Secure Client versions should be remediated promptly to reduce VPN disruption risk.

Technical view

The issue is an out-of-bounds read in Cisco Secure Client Software, formerly AnyConnect. Exploitation requires valid local credentials on a multi-user system while another user is accessing the client. Successful exploitation can crash the VPN Agent service, causing denial of service.

Likely exposure

Exposure is most relevant where affected Cisco Secure Client versions 4.9, 4.10, or 5.0 are installed on shared or multi-user endpoints. Single-user managed workstations have lower practical risk, but still need version validation.

Exploitation context

The CVE is not listed as KEV in the provided bundle, and no cited source states active exploitation. The attacker must already have valid credentials on the affected system, making this a local availability risk rather than remote compromise.

Researcher notes

The weakness is mapped to CWE-125 and affects availability only under the CVSS vector provided. The source bundle does not include explicit fixed-version or workaround details, so remediation should be validated directly against Cisco's advisory.

Mitigation direction

  • Inventory Cisco Secure Client installations and compare versions with the affected version list.
  • Use Cisco's advisory to identify supported fixed releases or official workaround guidance.
  • Prioritize shared workstations, jump hosts, labs, and VDI systems using affected versions.
  • Restrict unnecessary local access to systems where Cisco Secure Client is installed.
  • Monitor VPN Agent crashes on shared endpoints until remediation is complete.

Validation and detection

  • Check endpoint software inventory for affected Cisco Secure Client versions.
  • Confirm whether impacted systems are single-user or multi-user environments.
  • Review service logs for unexplained VPN Agent crashes or repeated restarts.
  • Track remediation status against Cisco advisory guidance.
  • Confirm upgraded clients no longer match affected version entries.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-125: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2023-20240 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
2ADP providers
2Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6cisco

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2023-20240Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Secure Client4.9.00086, 4.9.01095, 4.9.02028, 4.9.03047, 4.9.03049, 4.9.04043, 4.9.04053, 4.9.05042, 4.9.06037, 4.10.00093, 4.10.01075, 4.10.02086, 4.10.03104, 4.10.04065, 4.10.04071, 4.10.05085, 4.10.05095, 4.10.05111, 4.10.06079, 4.10.06090, 4.10.07061, 4.10.07062, 4.10.07073, 5.0.00238, 5.0.00529, 5.0.00556, 5.0.01242, 5.0.02075, 5.0.03072, 5.0.03076Listed
Weakness

CWE details

CWE-125

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs