Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-71920— DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout

Quick assessment

Affected
DrayTek Corporation VigorSwitch G2540xs
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

DrayTek VigorSwitch是中国DrayTek公司的一款网络交换机。 DrayTek VigorSwitch存在异常处理不当漏洞，该漏洞源于formlogout函数缺少对空或缺失Cookie标头的检查，可能导致具有有效管理凭据的远程攻击者通过特制请求使服务崩溃，造成拒绝服务。

CVSS 4.9 · Medium EPSS 0.56% · P46

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 28

VendorProduct Version RangeStatus
DrayTek Corporation VigorSwitch FX2120 < 3.9.10 affected
DrayTek Corporation VigorSwitch G1280 < 2.9.10 affected
DrayTek Corporation VigorSwitch G1282 < 2.9.10 affected
DrayTek Corporation VigorSwitch G2100 < 2.9.10 affected
DrayTek Corporation VigorSwitch G2121 < 2.9.10 affected
DrayTek Corporation VigorSwitch G2280x < 2.9.10 affected
DrayTek Corporation VigorSwitch G2282x < 2.10.6 affected
DrayTek Corporation VigorSwitch G2540x < 2.9.10 affected
DrayTek Corporation VigorSwitch G2540xs < 3.9.10 affected
DrayTek Corporation VigorSwitch G2542x < 3.10.6 affected
DrayTek Corporation VigorSwitch P1280 < 2.9.10 affected
DrayTek Corporation VigorSwitch P1281x < 2.9.10 affected
DrayTek Corporation VigorSwitch P1282 < 2.9.10 affected
DrayTek Corporation VigorSwitch P2100 < 2.9.10 affected
DrayTek Corporation VigorSwitch P2121 < 2.9.10 affected
DrayTek Corporation VigorSwitch P2280x < 2.9.10 affected
DrayTek Corporation VigorSwitch P2282x < 2.10.6 affected
DrayTek Corporation VigorSwitch P2540x < 2.9.10 affected
DrayTek Corporation VigorSwitch P2540xs < 3.9.10 affected
DrayTek Corporation VigorSwitch P2542x < 3.10.6 affected
DrayTek Corporation VigorSwitch P2542xh < 3.10.6 affected
DrayTek Corporation VigorSwitch PQ2121x < 2.9.10 affected
DrayTek Corporation VigorSwitch PQ2200xb < 2.9.10 affected
DrayTek Corporation VigorSwitch PQ2300xb < 2.10.7 affected
DrayTek Corporation VigorSwitch PX2060 < 2.9.10 affected
DrayTek Corporation VigorSwitch Q2121x < 2.9.10 affected
DrayTek Corporation VigorSwitch Q2200x < 2.9.10 affected
DrayTek Corporation VigorSwitch Q2300x < 2.10.7 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-71920

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
空指针解引用
Source: CVE Program / CVE List V5
Vulnerability Title
DrayTek VigorSwitch 异常处理不当漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
DrayTek VigorSwitch是中国DrayTek公司的一款网络交换机。 DrayTek VigorSwitch存在异常处理不当漏洞，该漏洞源于formlogout函数缺少对空或缺失Cookie标头的检查，可能导致具有有效管理凭据的远程攻击者通过特制请求使服务崩溃，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
DrayTek Corporation VigorSwitch G2540xs 0 ~ 3.9.10 -
DrayTek Corporation VigorSwitch P2540xs 0 ~ 3.9.10 -
DrayTek Corporation VigorSwitch FX2120 0 ~ 3.9.10 -
DrayTek Corporation VigorSwitch G2282x 0 ~ 2.10.6 -
DrayTek Corporation VigorSwitch P2282x 0 ~ 2.10.6 -
DrayTek Corporation VigorSwitch Q2300x 0 ~ 2.10.7 -
DrayTek Corporation VigorSwitch PQ2300xb 0 ~ 2.10.7 -
DrayTek Corporation VigorSwitch G2542x 0 ~ 3.10.6 -
DrayTek Corporation VigorSwitch P2542x 0 ~ 3.10.6 -
DrayTek Corporation VigorSwitch P2542xh 0 ~ 3.10.6 -
DrayTek Corporation VigorSwitch PX2060 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G1280 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P1280 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P1281x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G1282 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P1282 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G2121 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P2121 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch PQ2121x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch Q2121x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G2280x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P2280x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch Q2200x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch PQ2200xb 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G2100 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P2100 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch G2540x 0 ~ 2.9.10 -
DrayTek Corporation VigorSwitch P2540x 0 ~ 2.9.10 -

II. Public POCs for CVE-2026-71920

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-71920

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-71920 (2)

Same Patch Batch · DrayTek Corporation · 2026-08-24 · 40 CVEs total

CVE-2026-71914 9.8 CRITICAL DrayTek VigorAP Multiple Models Pre-Authentication OS Command Injection via dray_apm
CVE-2026-71921 9.8 CRITICAL DrayTek VigorSwitch Multiple Models Pre-Authentication OS Command Injection via setget.cgi
CVE-2026-71933 9.1 CRITICAL DrayTek VigorSwitch Multiple Models Missing Authorization in Syslog Functions
CVE-2026-71922 7.5 HIGH DrayTek VigorSwitch Multiple Models Pre-Authentication NULL Pointer Dereference via setget
CVE-2026-71934 7.2 HIGH DrayTek VigorSwitch Multiple Models Buffer Overflow via pingtrace
CVE-2026-71905 7.2 HIGH DrayTek VigorAP Multiple Models OS Command Injection via ExportSettings
CVE-2026-71919 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via sysreboot
CVE-2026-71910 7.2 HIGH DrayTek VigorAP Multiple Models OS Command Injection via apautotest
CVE-2026-71906 7.2 HIGH DrayTek VigorAP Multiple Models OS Command Injection via setLan
CVE-2026-71912 7.2 HIGH DrayTek VigorAP Multiple Models Buffer Overflow via apautotest
CVE-2026-71917 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via pingtrace
CVE-2026-71907 7.2 HIGH DrayTek VigorAP Multiple Models OS Command Injection via setcamset
CVE-2026-71925 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via getDetail
CVE-2026-71915 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via jsonstatus
CVE-2026-71923 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via auth_set
CVE-2026-71935 7.2 HIGH DrayTek VigorSwitch Multiple Models Buffer Overflow via webBackupAction
CVE-2026-71941 7.2 HIGH DrayTek VigorSwitch Multiple Models Buffer Overflow via diag_logmail
CVE-2026-71938 7.2 HIGH DrayTek VigorSwitch Multiple Models Buffer Overflow via switch_lan_gvrp
CVE-2026-71939 7.2 HIGH DrayTek VigorSwitch Multiple Models Buffer Overflow via acl_general_setup Add ACE
CVE-2026-71918 7.2 HIGH DrayTek VigorSwitch Multiple Models OS Command Injection via webBackupAction

Showing top 20 of 40 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: VigorSwitch G2540xs
Same vendor: DrayTek Corporation
Same weakness: CWE-476