CVE-2023-27992 (GCVE-0-2023-27992)
Vulnerability from cvelistv5 – Published: 2023-06-19 11:42 – Updated: 2025-10-21 23:05Summary
The pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware versions prior to V5.21(AATB.11)C0, and NAS542 firmware versions prior to V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request.
Severity
9.8 (Critical)
SSVC
Exploitation: active
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-01-27 22:16 UTC
CWE
- CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://www.zyxel.com/global/en/support/security-… | |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
Impacted products
3 products
| Vendor | Product | Version | |
|---|---|---|---|
| Zyxel | NAS326 firmware |
Affected:
< V5.21(AAZF.14)C0
|
|
| Zyxel | NAS540 firmware |
Affected:
< V5.21(AATB.11)C0
|
|
| Zyxel | NAS542 firmware |
Affected:
< V5.21(ABAG.11)C0
|
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: ba5a5ed6-00bb-4357-88e5-8890c090c50f
Exploited: Yes
Timestamps
First Seen: 2023-06-23
Asserted: 2023-06-23
Scope
Notes: Zyxel Multiple NAS Devices Command Injection Vulnerability | Affected: Zyxel / Multiple Network-Attached Storage (NAS) Devices | Description: Multiple Zyxel network-attached storage (NAS) devices contain a pre-authentication command injection vulnerability that could allow an unauthenticated attacker to execute commands remotely via a crafted HTTP request. | Required action: Apply updates per vendor instructions. | Due date: 2023-07-14 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-pre-authentication-command-injection-vulnerability-in-nas-products; https://nvd.nist.gov/vuln/detail/CVE-2023-27992
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-78 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | Multiple Network-Attached Storage (NAS) Devices |
| Due Date | 2023-07-14 |
| Date Added | 2023-06-23 |
| Vendorproject | Zyxel |
| Vulnerabilityname | Zyxel Multiple NAS Devices Command Injection 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: 6eed0478-2084-4c3f-b97d-39aab4ea8f02
Exploited: Yes
Timestamps
First Seen: 2023-06-23
Asserted: 2023-06-23
Scope
Notes: The pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware... | Affected: Zyxel / NAS326 firmware, NAS540 firmware, NAS542 firmware | CVSS: 9.8 (CRITICAL) | EPSS: 0.82828 | 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 | The pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware... |
| Cve Id | CVE-2023-27992 |
| Vendor | Zyxel |
| Ghsa Id | None |
| Product | NAS326 firmware, NAS540 firmware, NAS542 firmware |
| Added Date | 2023-06-23T00:00:00.000Z |
| Cvss Score | 9.8 |
| Epss Score | 0.82828 |
| Previous Ids | |
| Cvss Severity | CRITICAL |
| Virtual Patch | False |
| Cvss Estimated | False |
| Epss Percentile | 0.99662 |
| Used In Malware | unknown |
| Vulnerability Id | CVE-2023-27992 |
| 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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