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CVE-2026-71941

HIGH 8.6

Published 2026-08-24 · Last modified 2026-08-27

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the diag_logmail function. The vulnerability is caused by concatenating multiple smtpReceiver email addresses into a fixed-size buffer without checking the remaining buffer size. 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.

ELEVATED IMPACT

Severe if exploited (CVSS 8.6), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 39th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

8.6CVSS 4.0 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires an admin / high-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ✓Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-71941/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-71941/poc.json

Affected

Vendors Draytek Corporation

Products Vigorswitch G2540xs Vigorswitch P2540xs Vigorswitch Fx2120 Vigorswitch G2282x Vigorswitch P2282x Vigorswitch Q2300x Vigorswitch Pq2300xb Vigorswitch G2542x Vigorswitch P2542x Vigorswitch P2542xh Vigorswitch Px2060 Vigorswitch G1280

Weakness (CWE)

  • CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

All CVSS metrics

  • HIGH 8.6 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
  • HIGH 7.2 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
  • HIGH 8.6 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • HIGH 7.2 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

References

Advisories

Sources: NVD · CVE.org · EPSS