Threat Investigation
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CVE-2026-71936

High

Description

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the sysreboot function. The vulnerability is caused by unsafe concatenation of split valueN data into a fixed-size buffer. A remote attacker can trigger this vulnerability via crafted input, causing a denial of service or potentially executing arbitrary commands. Exploitation requires valid administrative credentials for the device's web management interface.

SeverityHigh
CVSS7.2
Exploit probability53. percentile0.7%
ProductVigorSwitch G2540xs
PublishedAug 24, 2026
First seenAug 24, 2026
Weakness typeCWE-120CWE-120

How to fix

Update
  • DrayTek Corporation VigorSwitch G2540xs3.9.10 or later
  • DrayTek Corporation VigorSwitch P2540xs3.9.10 or later
  • DrayTek Corporation VigorSwitch FX21203.9.10 or later
  • DrayTek Corporation VigorSwitch G2282x2.10.6 or later
  • DrayTek Corporation VigorSwitch P2282x2.10.6 or later
  • DrayTek Corporation VigorSwitch Q2300x2.10.7 or later
  • DrayTek Corporation VigorSwitch PQ2300xb2.10.7 or later
  • DrayTek Corporation VigorSwitch G2542x3.10.6 or later
  • DrayTek Corporation VigorSwitch P2542x3.10.6 or later
  • DrayTek Corporation VigorSwitch P2542xh3.10.6 or later
  • DrayTek Corporation VigorSwitch PX20602.9.10 or later
  • DrayTek Corporation VigorSwitch G12802.9.10 or later
Vendor advisories

Affected products

ProductAffected versionsFixed in
DrayTek Corporation VigorSwitch G2540xsv < 3.9.103.9.10
DrayTek Corporation VigorSwitch P2540xsv < 3.9.103.9.10
DrayTek Corporation VigorSwitch FX2120v < 3.9.103.9.10
DrayTek Corporation VigorSwitch G2282xv < 2.10.62.10.6
DrayTek Corporation VigorSwitch P2282xv < 2.10.62.10.6
DrayTek Corporation VigorSwitch Q2300xv < 2.10.72.10.7
DrayTek Corporation VigorSwitch PQ2300xbv < 2.10.72.10.7
DrayTek Corporation VigorSwitch G2542xv < 3.10.63.10.6
DrayTek Corporation VigorSwitch P2542xv < 3.10.63.10.6
DrayTek Corporation VigorSwitch P2542xhv < 3.10.63.10.6
DrayTek Corporation VigorSwitch PX2060v < 2.9.102.9.10
DrayTek Corporation VigorSwitch G1280v < 2.9.102.9.10
DrayTek Corporation VigorSwitch P1280v < 2.9.102.9.10
DrayTek Corporation VigorSwitch P1281xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch G1282v < 2.9.102.9.10
DrayTek Corporation VigorSwitch P1282v < 2.9.102.9.10
DrayTek Corporation VigorSwitch G2121v < 2.9.102.9.10
DrayTek Corporation VigorSwitch P2121v < 2.9.102.9.10
DrayTek Corporation VigorSwitch PQ2121xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch Q2121xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch G2280xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch P2280xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch Q2200xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch PQ2200xbv < 2.9.102.9.10
DrayTek Corporation VigorSwitch G2100v < 2.9.102.9.10
DrayTek Corporation VigorSwitch P2100v < 2.9.102.9.10
DrayTek Corporation VigorSwitch G2540xv < 2.9.102.9.10
DrayTek Corporation VigorSwitch P2540xv < 2.9.102.9.10

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