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Vulnerability · Published Aug 24, 2026 · Assigned by VulnCheck

CVE-2026-71935DrayTek VigorSwitch Multiple Models Buffer Overflow via webBackupAction

High 7.2

In plain English

A high-severity buffer overflow in VigorSwitch FX2120 from DrayTek Corporation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities).

Severity (CVSS 3.1)7.2High
Exploit odds (30 days)0.7%top 47.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the webBackupAction function. The vulnerability is caused by repeated string concatenation of the pathN, valueN, key, and option fields into fixed-size stack buffers without total length checks. 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.

Affected products (as reported)

VendorProductVersions
DrayTek Corporation VigorSwitch G2540xs 0 – before 3.9.10
DrayTek Corporation VigorSwitch P2540xs 0 – before 3.9.10
DrayTek Corporation VigorSwitch FX2120 0 – before 3.9.10
DrayTek Corporation VigorSwitch G2282x 0 – before 2.10.6
DrayTek Corporation VigorSwitch P2282x 0 – before 2.10.6
DrayTek Corporation VigorSwitch Q2300x 0 – before 2.10.7
DrayTek Corporation VigorSwitch PQ2300xb 0 – before 2.10.7
DrayTek Corporation VigorSwitch G2542x 0 – before 3.10.6
DrayTek Corporation VigorSwitch P2542x 0 – before 3.10.6
DrayTek Corporation VigorSwitch P2542xh 0 – before 3.10.6
DrayTek Corporation VigorSwitch PX2060 0 – before 2.9.10
DrayTek Corporation VigorSwitch G1280 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1280 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1281x 0 – before 2.9.10
DrayTek Corporation VigorSwitch G1282 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1282 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2121 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2121 0 – before 2.9.10
DrayTek Corporation VigorSwitch PQ2121x 0 – before 2.9.10
DrayTek Corporation VigorSwitch Q2121x 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2280x 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2280x 0 – before 2.9.10
DrayTek Corporation VigorSwitch Q2200x 0 – before 2.9.10
DrayTek Corporation VigorSwitch PQ2200xb 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2100 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2100 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2540x 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2540x 0 – before 2.9.10

Weakness: CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

References