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CVE Record

CVE-2021-1278: Cisco SD-WAN Denial of Service Vulnerabilities

Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-1278 is a high-severity Cisco SD-WAN availability risk. A remote attacker without credentials could crash or disrupt an affected device, potentially interrupting WAN connectivity or SD-WAN services. The provided sources do not identify affected versions or a confirmed fix in this bundle.

Executive priority

Prioritize this as a high availability issue for sites relying on Cisco SD-WAN. Business impact is service disruption, not data theft based on the provided CVSS impacts. Urgency depends on exposure and Cisco advisory applicability.

Technical view

The CVE describes multiple Cisco SD-WAN DoS vulnerabilities with CVSS 3.1 score 8.6. The vector is network-accessible, low complexity, unauthenticated, and requires no user interaction. Impact is availability only, with no stated confidentiality or integrity impact. The CVE maps to CWE-119.

Likely exposure

Exposure applies to organizations running Cisco SD-WAN Solution devices. The bundle does not list affected versions, CPEs, interfaces, or component names, so validation must start with Cisco SD-WAN asset inventory and the Cisco advisory.

Exploitation context

The source bundle says the issue is remotely reachable and unauthenticated. It does not provide evidence of active exploitation, and KEV status is false. Treat exploit status as unconfirmed from these sources.

Researcher notes

The bundle lacks technical detail about vulnerable components, exact versions, and remediation text. Do not infer exploitability beyond unauthenticated remote DoS. Use the Cisco advisory as the controlling source for affected software and fixed-release guidance.

Mitigation direction

  • Review Cisco advisory cisco-sa-sdwan-dosmulti-48jJuEUP for affected releases and fixes.
  • Inventory Cisco SD-WAN devices and software versions.
  • Prioritize patching or vendor-recommended remediation for exposed SD-WAN infrastructure.
  • Restrict untrusted network access to SD-WAN device interfaces where operationally feasible.
  • Monitor SD-WAN device availability, crashes, and unexpected restarts.

Validation and detection

  • Confirm whether Cisco SD-WAN Solution is deployed in the environment.
  • Compare deployed versions against Cisco advisory affected-version guidance.
  • Check whether affected devices are reachable from untrusted networks.
  • Review logs and monitoring for DoS symptoms or unexplained device restarts.
  • Document compensating access controls until vendor remediation is confirmed.
Prepared
Confidence
medium
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-119: 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.

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cve · low confidence lookup

CVE-2021-1278 mapping review

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

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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
0Timeline events
0ADP providers
2Source links

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
8.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.6High
CVSS 3.1 vector shape for CVE-2021-1278Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco SD-WAN Solutionn/aListed
Weakness

CWE details

CWE-119

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