How do I check whether I am affected by CVE-2026-42023?

Open the router admin UI and read the firmware version. TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327 is confirmed vulnerable; other builds are untested. Also check whether the admin web UI is reachable from the WAN side (remote management setting), or from untrusted LAN/guest clients.

What is the fix for CVE-2026-42023?

No fixed firmware published as of 2026-10-23 (unknown). Check totolink.net X2000R product page for new firmware. Mitigate: turn off WAN remote management, restrict admin UI to trusted LAN hosts, use a strong unique admin password, replace the device if no patch appears.

Who is not affected by CVE-2026-42023?

Not affected if: auth-required, other-firmware-versions, wan-management-disabled.

Live › vulnerability › CVE-2026-42023

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critical9.1Infrastructure

TOTOLINK X2000R router: stack overflow in IPv6 setup lets attackers run code

Stack buffer overflow in the static_ipv6 parameter of formIpv6Setup in the boa web server of the TOTOLINK X2000R, found by Cisco Talos. A logged-in admin can send one crafted POST and run code on the router. Only build B20250421.1327 is listed as tested. TOTOLINK has published no fix. Talos shows crash details but no working exploit.

Summary written from the sources below. Check the originals before acting.

CVSS 3.x

9.1

critical

scored by [email protected]

known so far5 of 6

missing: exploitation

First public: Oct 20, 2026 UTC
Last modified: Oct 23, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.

Why it is critical, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: Yes.
Needs a special setup: Not known from the sources.
Reachable from: network.
Worst case: Arbitrary code runs on the router, giving the attacker control of the device.
CVSS said: 9.1. The facts above say medium; we keep the sources' critical until an analyst looks.

Who is affected

1 product

Know the next one before it finds you.

Add to Slack

Live › vulnerability › CVE-2026-42023

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critical9.1Infrastructure

TOTOLINK X2000R router: stack overflow in IPv6 setup lets attackers run code

Summary written from the sources below. Check the originals before acting.

CVSS 3.x

9.1

critical

scored by [email protected]

known so far5 of 6

missing: exploitation

First public: Oct 20, 2026 UTC
Last modified: Oct 23, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.

Why it is critical, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: Yes.
Needs a special setup: Not known from the sources.
Reachable from: network.
Worst case: Arbitrary code runs on the router, giving the attacker control of the device.
CVSS said: 9.1. The facts above say medium; we keep the sources' critical until an analyst looks.

Who is affected

1 product

Know the next one before it finds you.

Add to Slack

TOTOLINK X2000R router: stack overflow in IPv6 setup lets attackers run code

Why it is critical, and not just CVSS

Who is affected

Know the next one before it finds you.

TOTOLINK X2000R router: stack overflow in IPv6 setup lets attackers run code

Why it is critical, and not just CVSS

Who is affected

Know the next one before it finds you.

How to check

The fix

Who had it, and when

What the sources say, verbatim

Sources