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New CVE Detected

CVE-2026-98432 (this post shows a partial list of MPTCP-capable assets)

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TL;DR

What is this vulnerability?

A race condition in the Linux kernel’s TCP/IP stack, specifically in its MPTCP (Multipath TCP) implementation. Depending on how the race plays out, exploiting it can cause a denial of service (DoS) or remote code execution (RCE).

How did we detect these assets?

We continuously probe the open ports of our customers’ assets with TCP packets to find out whether MPTCP is enabled. Every asset that our scan reached and that has MPTCP enabled is listed here.

The list is partial. Some assets don’t answer these probes for reasons other than having the protective configuration in place, so an asset missing from the list may still be affected.

Summary

This post lists only the subset of CVE-2026-98432-potentially-affected assets that IONIX has externally confirmed answer an MPTCP-capable TCP handshake — the one precondition every real-world exploitation of this bug (including Anthropic’s own disclosed exploit) has required. See our original post on CVE-2026-98432 for the full technical write-up, affected software list, and mitigation steps.

IONIX detection of affected assets

The broader CVE-2026-98432 post lists all internet-facing Linux hosts that pass our exclusion filter (not fronted by a known cloud/CDN/WAF provider).

This post is narrower: IONIX sent each listed asset a single, non-destructive TCP SYN carrying the IPv4 MPTCP MP_CAPABLE option, from a disclosed, non-proxied vantage point, and confirmed it replies with its own MP_CAPABLE option — proof the host runs a live MPTCP listener, the one precondition every demonstrated real-world exploit of this CVE has needed. We did not attempt to trigger the underlying race condition itself (doing so risks crashing or corrupting memory on the target), so a match here is not proof of successful exploitation — only that this specific precondition is present and externally reachable right now.

This check is re-run on a rolling basis; an asset currently absent from this narrower list has not necessarily been ruled out, only not yet (re)confirmed. We recommend prioritizing the assets in this narrower list first, then continuing through the broader list.

Mitigation

See the original CVE-2026-98432 post for full remediation guidance. In short: patch to a fixed kernel version, or as an interim measure, disable MPTCP (sysctl -w net.mptcp.enabled=0) or drop inbound IPv4 TCP packets carrying IP options at the network edge.

References

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How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
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