CVE-2026-82539
Remote memory-corruption in TOTOLINK A720R MAC filtering CGI (cstecgi.cgi) enabling potential RCE.
Is CVE-2026-82539 being exploited?
Not confirmed. CVE-2026-82539 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 0.60% probability of exploitation in the next 30 days.
How severe is CVE-2026-82539?
CVE-2026-82539 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-2026-82539?
Not known from our data. No patch reference has been recorded for CVE-2026-82539, 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-2026-82539 affect?
CVE-2026-82539 affects TOTOLINK A720R firmware 4.1.5cu.630_B20250509, cstecgi.cgi -> setMacFilterRules (MAC Filtering). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-82539?
Isolate affected devices, block WAN access to router management, apply vendor patch when released
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote memory corruption via setMacFilterRules 'desc' may allow remote code execution or device crash/DoS.
Immediate action required
- affected4.1.5cu.630_B20250509
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.