Quick answers
- Is CVE-2026-71939 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-71939 being exploited in the wild.
- How severe is CVE-2026-71939?
- 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-2026-71939?
- A patch was published on 2026-08-24: Firmware updates released for affected models Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-71939 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-71939?
- 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 acl_general_setup function's Add ACE (Access Control Entry) feature. The root cause is that the name field is copied into a fixed-size buffer without length validation, allowing an attacker to overflow the buffer with crafted input. Attack vector is network-based via the web management interface; however, exploitation requires valid administrative credentials and authentication. An attacker with administrative access can trigger a denial of service (device crash) or potentially achieve arbitrary code execution on the affected appliance. Patches are available in firmware versions specified by DrayTek for each affected model.
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: Firmware updates released for affected models