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CVE Record

CVE-2026-20122: Cisco Catalyst SD-WAN Manager Arbitrary File Overwrite Vulnerability

A vulnerability in the API of Cisco Catalyst SD-WAN Manager could allow an authenticated, remote attacker to overwrite arbitrary files on the local file system. To exploit this vulnerability, the attacker must have valid read-only credentials with API access on the affected system. This vulnerability is due to improper file handling on the API interface of an affected system. An attacker could exploit this vulnerability by uploading a malicious file on the local file system. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system and gain vmanage user privileges.

MediumCVSS 5.4Known exploitedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Cisco Catalyst SD-WAN Manager has an API flaw that lets a logged-in remote user with read-only API access overwrite local files. Successful abuse could give the attacker vmanage user privileges. This is not described as unauthenticated or actively exploited in the provided sources.

Executive priority

Treat as moderate priority. It requires credentials, but it affects the SD-WAN management plane and can elevate privileges on the Manager. Prioritize environments with exposed APIs, many API users, or weak credential controls.

Technical view

CVE-2026-20122 is an improper file handling issue in the Cisco Catalyst SD-WAN Manager API. An authenticated remote attacker with valid read-only API credentials can upload a malicious file to overwrite arbitrary local files, potentially gaining vmanage user privileges. CVSS v3.1 is 5.4, medium severity.

Likely exposure

Exposure applies to Cisco Catalyst SD-WAN Manager deployments running affected releases listed in the CVE data. Risk is highest where the Manager API is reachable beyond tightly controlled administration networks, or where read-only API credentials are broadly issued, reused, or compromised.

Exploitation context

The provided CISA KEV reference does not indicate known exploited status, and the bundle provides no public exploit confirmation. Exploitation requires valid credentials with API access, lowering opportunistic risk but raising concern for compromised accounts, insiders, or weak credential governance.

Researcher notes

Core evidence comes from Cisco/CVE data. The bundle lists many affected releases but does not include fixed versions or detailed workaround text. Do not assume active exploitation. Focus validation on authenticated API reachability, credential scope, version status, and Cisco advisory updates.

Mitigation direction

  • Review Cisco’s advisory for fixed releases or official workarounds.
  • Upgrade affected Cisco Catalyst SD-WAN Manager systems per Cisco guidance.
  • Restrict Manager API access to trusted administration networks only.
  • Limit and review read-only accounts with API access.
  • Rotate API credentials if compromise is suspected.
  • Monitor for unexpected local file changes on Manager systems.

Validation and detection

  • Inventory all Cisco Catalyst SD-WAN Manager instances and versions.
  • Compare running versions with Cisco’s affected-release information.
  • Identify accounts with read-only API access.
  • Confirm API exposure is limited to trusted management paths.
  • Review logs for unusual API upload or file-write activity.
  • Verify remediation against Cisco’s current advisory.
Prepared
Confidence
medium
Sources
4

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-648: 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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description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-20122 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
Medium
CVSS
5.4 (3.1)
Known Exploited
Yes
Published

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

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
3Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

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
5.4CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N2.82.5Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.4Medium
CVSS 3.1 vector shape for CVE-2026-20122Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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 Catalyst SD-WAN Manager20.1.12, 19.2.1, 18.4.4, 18.4.5, 20.1.1.1, 20.1.1, 19.3.0, 19.2.2, 19.2.099, 18.3.6, 18.3.7, 19.2.0, 18.3.8, 19.0.0, 19.1.0, 18.4.302, 18.4.303, 19.2.097, 19.2.098, 17.2.10, 18.3.6.1, 19.0.1a, 18.2.0, 18.4.3, 18.4.1, 17.2.8, 18.3.3.1, 18.4.0, 18.3.1, 17.2.6, 17.2.9, 18.3.4, 17.2.5, 18.3.1.1, 18.3.5, 18.4.0.1, 18.3.3, 17.2.7, 17.2.4, 18.3.0, 19.2.3, 18.4.501_ES, 20.3.1, 20.1.2, 19.2.929, 19.2.31, 20.3.2, 19.2.32, 20.3.2_925, 20.3.2.1, 20.3.2.1_927, 18.4.6, 20.1.2_937, 20.4.1, 20.3.2_928, 20.3.2_929, 20.4.1.0.1, 20.3.2.1_930, 19.2.4, 20.5.0.1.1, 20.4.1.1, 20.3.3, 19.2.4.0.1, 20.3.2_937, 20.3.3.1, 20.5.1, 20.1.3, 20.3.3.0.4, 20.3.3.1.2, 20.3.3.1.1, 20.4.1.2, 20.3.3.0.2, 20.4.1.1.5, 20.4.1.0.01, 20.4.1.0.02, 20.3.3.1.7, 20.3.3.1.5, 20.5.1.0.1, 20.3.3.1.10, 20.3.3.0.8, 20.4.2, 20.4.2.0.1, 20.3.4, 20.3.3.0.14, 19.2.4.0.8, 19.2.4.0.9, 20.3.4.0.1, 20.3.2.0.5, 20.6.1, 20.5.1.0.2, 20.3.3.0.17, 20.6.1.1, 20.6.0.18.3, 20.3.2.0.6, 20.6.0.18.4, 20.4.2.0.2, 20.3.3.0.16, 20.3.4.0.5, 20.6.1.0.1, 20.3.4.0.6, 20.6.2, 20.7.1EFT2, 20.3.4.0.9, 20.3.4.0.11, 20.4.2.0.4, 20.3.3.0.18, 20.7.1, 20.6.2.1, 20.3.4.1, 20.5.1.1, 20.4.2.1, 20.4.2.1.1, 20.3.4.1.1, 20.3.813, 20.3.4.0.19, 20.4.2.2.1, 20.5.1.2, 20.3.4.2, 20.3.814, 20.4.2.2, 20.6.2.2, 20.3.4.2.1, 20.7.1.1, 20.3.4.1.2, 20.6.2.2.2, 20.3.4.0.20, 20.6.2.2.3, 20.4.2.2.2, 20.3.5, 20.6.2.0.4, 20.4.2.2.3, 20.3.4.0.24, 20.6.2.2.7, 20.6.3, 20.3.4.2.2, 20.4.2.2.4, 20.7.1.0.2, 20.8.1, 20.3.5.0.8, 20.3.5.0.9, 20.4.2.2.8, 20.3.5.0.7, 20.6.3.0.7, 20.6.3.0.5, 20.6.3.0.10, 20.6.3.0.2, 20.7.2, 20.9.1EFT2, 20.6.3.0.11, 20.6.3.1, 20.6.3.0.14, 20.6.4, 20.9.1, 20.6.3.0.19, 20.6.3.0.18, 20.3.6, 20.9.1.1, 20.6.3.0.23, 20.6.4.0.4, 20.6.3.0.25, 20.6.5, 20.6.3.0.27, 20.9.2, 20.9.2.1, 20.6.3.0.29, 20.6.3.0.31, 20.6.3.0.32, 20.10.1, 20.6.3.0.33, 20.9.2.0.01, 20.9.1_LI_Images, 20.10.1_LI_Images, 20.9.2_LI_Images, 20.3.7, 20.9.3, 20.6.5.1, 20.11.1, 20.11.1_LI_Images, 20.9.3_LI_ Images, 20.6.3.1.1, 20.9.3.0.2, 20.6.5.1.2, 20.9.3.0.3, 20.4.2.3, 20.6.3.2, 20.6.4.1, 20.6.3.0.38, 20.6.3.0.39, 20.3.5.1, 20.3.4.3, 20.9.3.1, 20.3.3.2, 20.6.5.2, 20.3.7.1, 20.10.1.1, 20.6.5.2.1, 20.3.4.0.25, 20.6.2.2.4, 20.6.1.2, 20.11.1.1, 20.9.3.0.5, 20.3.4.0.26, 20.6.5.1.3, 20.6.3.0.40, 20.1.3.1, 20.9.2.2, 20.6.5.2.3, 20.6.5.1.4, 20.6.5.3, 20.6.3.0.41, 20.9.3.0.7, 20.6.5.1.5, 20.9.3.0.4, 20.6.4.0.19, 20.6.5.1.6, 20.9.3.0.8, 20.6.3.3, 20.3.7.2, 20.6.5.4, 20.6.5.1.7, 20.9.3.0.12, 20.6.4.2, 20.6.5.5, 20.9.3.2, 20.11.1.2, 20.6.3.4, 20.10.1.2, 20.6.5.1.9, 20.9.3.0.16, 20.6.3.0.45, 20.6.5.1.10, 20.9.3.0.17, 20.6.5.2.4, 20.6.4.0.21, 20.9.3.0.18, 20.6.3.0.46, 20.6.3.0.47, 20.9.2.3, 20.9.3.2_LI_Images, 20.9.3.0.21, 20.9.3.0.20, 20.9.4_LI_Images, 20.9.4, 20.6.5.1.11, 20.12.1, 20.12.1_LI_Images, 20.6.5.1.13, 20.9.3.0.23, 20.6.5.2.8, 20.9.4.1, 20.9.4.1_LI_Images, 20.9.3.0.25, 20.9.3.0.24, 20.6.5.1.14, 20.3.8, 20.6.6, 20.9.3.0.26, 20.6.3.0.51, 20.9.3.0.29, 20.12.2, 20.12.2_LI_Images, 20.6.6.0.1, 20.13.1_LI_Images, 20.9.4.0.4, 20.13.1, 20.9.4.1.1, 20.9.5, 20.9.5_LI_Images, 20.12.3_LI_Images, 20.12.3, 20.9.4.1.3, 20.6.7, 20.9.5.1, 20.9.5.1_LI_Images, 20.9.4.1.6, 20.14.1, 20.14.1_LI_Images, 20.9.5.2, 20.9.5.2.1, 20.9.5.2_LI_Images, 20.12.3.1, 20.12.4, 20.15.1_LI_Images, 20.15.1, 20.9.5.1.4, 20.9.5.2.7, 20.9.5.2.13, 20.9.6, 20.9.6_LI_Images, 20.9.5.2.14, 20.6.8, 20.12.4.0.03, 20.16.1, 20.16.1_LI_Images, 20.12.4_LI_Images, 20.9.5.2.16, 20.12.4.0.4, 20.12.401, 20.9.5.3, 20.9.5.3_LI_Images, 20.12.4.1_LI_Images, 20.12.4.1, 20.9.5.2.21, 20.9.6.0.3, 20.12.4.0.6, 20.15.2_LI_Images, 20.15.2, 20.12.4_Monthly_ES5, 20.12.5, 20.12.5_LI_Images, 20.9.7_LI _Images, 20.9.7, 20.15.3, 20.15.3_ LI _Images, 20.12.501, 20.12.5.1_LI_Images, 20.12.5.1, 20.12.5.2_LI_Images, 20.12.5.2, 20.15.3.1, 20.15.4_LI_Images, 20.15.4, 20.9.7.1_LI _Images, 20.9.7.1, 20.18.1, 20.18.1_LI_Images, 20.12.6_LI_Images, 20.12.6, 20.12.5.1.01, 20.9.8, 20.9.8_LI_Images, 20.18.2, 20.15.4.1_LI_Images, 20.15.4.1, 20.18.2_LI_Imagesunknown
Weakness

CWE details

CWE-648

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

CWE-648 · source CWE mapping

Incorrect Use of Privileged APIs

Incorrect Use of Privileged APIs represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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