CVE-2021-20123 (GCVE-0-2021-20123)
Vulnerability from cvelistv5 – Published: 2021-10-13 15:47 – Updated: 2025-10-21 23:25Summary
A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.
Severity
7.5 (High)
SSVC
Exploitation: active
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-03 12:29 UTC
CWE
- Path Traversal
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://www.tenable.com/security/research/tra-2021-42 | x_refsource_MISC |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| n/a | Draytek VigorConnect |
Affected:
1.6.0-B3
|
|
| draytek | vigorconnect |
Affected:
1.6.0
cpe:2.3:a:draytek:vigorconnect:1.6.0:beta3:*:*:*:*:*:* |
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: b7ece242-1fb4-494e-a0e6-51f88cd53dd6
Exploited: Yes
Timestamps
First Seen: 2024-09-03
Asserted: 2024-09-03
Scope
Notes: Draytek VigorConnect Path Traversal Vulnerability | Affected: DrayTek / VigorConnect | Description: Draytek VigorConnect contains a path traversal vulnerability in the DownloadFileServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges. | Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. | Due date: 2024-09-24 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://www.draytek.com/about/security-advisory/vigorconnect-software-security-vulnerability-(cve-2021-20123-cve-2021-20129); https://nvd.nist.gov/vuln/detail/CVE-2021-20123
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-22 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | VigorConnect |
| Due Date | 2024-09-24 |
| Date Added | 2024-09-03 |
| Vendorproject | DrayTek |
| Vulnerabilityname | Draytek VigorConnect Path Traversal Vulnerability |
| Knownransomwarecampaignuse | Unknown |
References
Created: 2026-10-02 08:09 CEST
| Updated: 2026-10-02 08:09 CEST
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: f85536f0-ab03-4906-b942-f83c35a3cd6d
Exploited: Yes
Timestamps
First Seen: 2024-09-03
Asserted: 2024-09-03
Scope
Notes: A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet... | Affected: Draytek / Draytek VigorConnect | CVSS: 7.5 (HIGH) | EPSS: 0.90234 | Used in malware: unknown | Not yet in CISA KEV: False
Evidence
Type: Public Report
Signal: Successful Exploitation
Confidence: 70%
Source: previdian
Details
| Feed | Previdian (previdian.com) |
|---|---|
| Title | A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet... |
| Cve Id | CVE-2021-20123 |
| Vendor | Draytek |
| Ghsa Id | None |
| Product | Draytek VigorConnect |
| Added Date | 2024-09-03T00:00:00.000Z |
| Cvss Score | 7.5 |
| Epss Score | 0.90234 |
| Previous Ids | |
| Cvss Severity | HIGH |
| Virtual Patch | False |
| Cvss Estimated | False |
| Epss Percentile | 0.99796 |
| Used In Malware | unknown |
| Vulnerability Id | CVE-2021-20123 |
| Ahead Of Cisa Kev | None |
| Not Yet In Cisa Kev | False |
References
Created: 2026-10-02 09:11 CEST
| Updated: 2026-10-02 09:11 CEST
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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