CVE-2026-71920 (GCVE-0-2026-71920)
Vulnerability from cvelistv5 – Published: 2026-08-24 17:07 – Updated: 2026-08-24 18:17
VLAI
EPSS
VEX
Title
DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
Summary
Multiple DrayTek VigorSwitch models contain a null pointer dereference vulnerability in the formlogout function. The vulnerability is caused by missing checks for an empty or absent Cookie header before string handling. A remote attacker can trigger this vulnerability via a crafted request to crash the service and cause a denial of service. Exploitation requires valid administrative credentials for the device's web management interface.
Severity
4.9 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-24 18:17 UTC
CWE
- CWE-476 - NULL Pointer Dereference
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://www.draytek.com/about/security-advisory/m… | vendor-advisory |
| https://www.vulncheck.com/advisories/draytek-vigo… | third-party-advisory |
Impacted products
28 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| DrayTek Corporation | VigorSwitch G2540xs |
Affected:
0 , < 3.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2540xs |
Affected:
0 , < 3.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch FX2120 |
Affected:
0 , < 3.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2282x |
Affected:
0 , < 2.10.6
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2282x |
Affected:
0 , < 2.10.6
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch Q2300x |
Affected:
0 , < 2.10.7
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch PQ2300xb |
Affected:
0 , < 2.10.7
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2542x |
Affected:
0 , < 3.10.6
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2542x |
Affected:
0 , < 3.10.6
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2542xh |
Affected:
0 , < 3.10.6
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch PX2060 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G1280 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P1280 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P1281x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G1282 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P1282 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2121 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2121 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch PQ2121x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch Q2121x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2280x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2280x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch Q2200x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch PQ2200xb |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2100 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2100 |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch G2540x |
Affected:
0 , < 2.9.10
(custom)
|
guessed | |
| DrayTek Corporation | VigorSwitch P2540x |
Affected:
0 , < 2.9.10
(custom)
|
guessed |
Date Public
2026-08-24 00:00
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"version": "3.1"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-476",
"description": "NULL Pointer Dereference",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-24T17:07:50.273Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://www.draytek.com/about/security-advisory/multiple-vulnerabilities-in-vigorswitch-series-august-2026/"
},
{
"name": "VulnCheck Advisory: DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout",
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/draytek-vigorswitch-multiple-models-null-pointer-dereference-via-formlogout"
}
],
"title": "DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout",
"x_generator": {
"engine": "vulncheck-endgame"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2026-71920",
"datePublished": "2026-08-24T17:07:50.273Z",
"dateReserved": "2026-08-08T16:37:44.518Z",
"dateUpdated": "2026-08-24T18:17:24.678Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
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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.