CVE-2026-71939
Authenticated buffer overflow in DrayTek VigorSwitch web GUI allows DoS or potential RCE.
Is CVE-2026-71939 being exploited?
Not confirmed. CVE-2026-71939 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.48% probability of exploitation in the next 30 days.
How severe is CVE-2026-71939?
CVE-2026-71939 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-71939?
Not known from our data. No patch reference has been recorded for CVE-2026-71939, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-71939 affect?
CVE-2026-71939 affects DrayTek VigorSwitch models (acl_general_setup Add ACE function). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-71939?
Restrict admin web access, enforce strong creds, disable web GUI if possible, apply vendor patch when available.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker with admin web credentials can trigger buffer overflow via crafted ACE name to cause DoS or possible remote code execution.
Immediate action required
- affected< 3.9.10
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- affected< 2.10.6
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- affected< 3.9.10
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- affected< 2.9.10
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- affected< 2.10.7
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- affected< 2.10.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.