CVE-2026-71931: DrayTek VigorSwitch command injection in tftp_upgrade

CVE-2026-71931 · Severity: high · CVSS 7.2 · Published 2026-08-24

DrayTek VigorSwitch is a network switching appliance used to manage and route network traffic in enterprise environments. A command injection vulnerability in the firmware update function allows authenticated administrators to execute arbitrary commands on the device with root privileges. This could enable an attacker with valid admin credentials to completely compromise the switch, disrupting network operations and potentially exfiltrating sensitive data.

Technologies: DrayTek VigorSwitch FX2120, DrayTek VigorSwitch G1280, DrayTek VigorSwitch G1282, DrayTek VigorSwitch G2100, DrayTek VigorSwitch G2121, DrayTek VigorSwitch G2280x, DrayTek VigorSwitch G2282x, DrayTek VigorSwitch G2540x, DrayTek VigorSwitch G2540xs, DrayTek VigorSwitch G2542x, DrayTek VigorSwitch P1280, DrayTek VigorSwitch P1281x, DrayTek VigorSwitch P1282, DrayTek VigorSwitch P2100, DrayTek VigorSwitch P2121, DrayTek VigorSwitch P2280x, DrayTek VigorSwitch P2282x, DrayTek VigorSwitch P2540x, DrayTek VigorSwitch P2540xs, DrayTek VigorSwitch P2542x, DrayTek VigorSwitch P2542xh, DrayTek VigorSwitch PQ2121x, DrayTek VigorSwitch PQ2200xb, DrayTek VigorSwitch PQ2300xb, DrayTek VigorSwitch PX2060, DrayTek VigorSwitch Q2121x, DrayTek VigorSwitch Q2200x, DrayTek VigorSwitch Q2300x. Vendors: DrayTek.

Quick answers

Is CVE-2026-71931 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-71931 being exploited in the wild.
How severe is CVE-2026-71931?
High severity, with a CVSS score of 7.2, published 24 August 2026.
Which products and versions are affected?
DrayTek VigorSwitch FX2120 before 3.9.10; DrayTek VigorSwitch G1280 before 2.9.10; DrayTek VigorSwitch G1282 before 2.9.10; DrayTek VigorSwitch G2100 before 2.9.10; and 24 more.
Is there a fix for CVE-2026-71931?
A patch was published on 2026-08-24: Patched firmware versions released for all affected models Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71931 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-71931?
Check whether you run DrayTek VigorSwitch FX2120, DrayTek VigorSwitch G1280, DrayTek VigorSwitch G1282 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is an OS command injection (CWE-78) in the tftp_upgrade function, caused by insufficient filtering of the filename parameter before it is concatenated into a shell command. An authenticated attacker on the network can supply specially crafted input to the TFTP upgrade interface to inject arbitrary shell commands. The commands execute with root privileges on the affected device. Exploitation requires valid administrative credentials and network access to the device's web management interface. Patched firmware versions are available for all affected VigorSwitch models and should be deployed immediately.

Affected products

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

Timeline

  • 2026-08-24: disclosed
  • 2026-08-24: patched: Patched firmware versions released for all affected models

References

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