CVE-2026-71937: DrayTek VigorSwitch buffer overflow in poe_schedule_profile

CVE-2026-71937 · Severity: high · CVSS 7.2 · Published 2026-08-24

DrayTek VigorSwitch network switches contain a buffer overflow vulnerability in the POE scheduling feature that allows authenticated administrators to crash the device or execute arbitrary commands. The affected switches are enterprise-grade network appliances used to provide power and connectivity to network devices. An attacker with valid admin credentials could exploit this flaw to take control of the switch, disrupting network operations or accessing sensitive network traffic.

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-2026-71937 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-71937 being exploited in the wild.
How severe is CVE-2026-71937?
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-2026-71937?
A patch was published on 2026-08-24. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71937 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-71937?
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 a classic buffer overflow (CWE-120) in the poe_schedule_profile function within the mainfunction.cgi component. The vulnerable code concatenates user-supplied fields (start_date, start_time, duration_time, how_often, weekdays, monthly_date, and cycle_duration) into fixed-size buffers without proper length validation. Exploitation requires network access to the device's web management interface and valid administrative credentials. A successful exploit can cause denial of service (device crash) or arbitrary command execution with device privileges. DrayTek has released patched firmware versions across all affected VigorSwitch models, with patch versions ranging from 2.9.10 to 3.10.6 depending on the model line.

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

References

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