DrayTek VigorSwitch formlogout null pointer dereference

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.9$0-$5k0.67+

Summaryinfo

A vulnerability categorized as problematic has been discovered in DrayTek VigorSwitch. The affected element is the function formlogout. The manipulation results in null pointer dereference. This vulnerability is reported as CVE-2026-71920. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in DrayTek VigorSwitch (affected version unknown). Affected is the function formlogout. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at draytek.com. This vulnerability is traded as CVE-2026-71920 since 08/08/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Additional levels of successful authentication are required for exploitation. There are known technical details, but no exploit is available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Vendor

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.9

VulDB Base Score: 4.9
VulDB Temp Score: 4.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.9
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/08/2026 CVE reserved
08/24/2026 +16 days Advisory disclosed
08/24/2026 +0 days VulDB entry created
08/24/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: draytek.com
Status: Not defined

CVE: CVE-2026-71920 (🔒)
GCVE (CVE): GCVE-0-2026-71920
GCVE (VulDB): GCVE-100-394752

Entryinfo

Created: 08/24/2026 19:44
Changes: 08/24/2026 19:44 (73)
Complete: 🔍
Cache ID: 216::103

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