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CVE-2026-68170

Critical Vulnerability: CVE-2026-68170

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix stale skb->sk reference on subflow close The backlog list is updated by mptcp_data_ready() under mptcp_data_lock(). The cleanup of backlog references to a closing subflow, however, was performed in mptcp_close_ssk(), before __mptcp_close_ssk() acquires the ssk lock, and while holding neither the ssk lock nor mptcp_data_lock(). Because that traversal ran without mptcp_data_lock(), concurrent softirq RX processing on

Friday, August 14, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-68170 is rated CRITICAL โ€” exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.

Executive Summary

In the Linux kernel, the following vulnerability has been resolved:

mptcp: fix stale skb->sk reference on subflow close

The backlog list is updated by mptcp_data_ready() under

mptcp_data_lock(). The cleanup of backlog references to a closing

subflow, however, was performed in mptcp_close_ssk(), before

__mptcp_close_ssk() acquires the ssk lock, and while holding neither

the ssk lock nor mptcp_data_lock().

Because that traversal ran without mptcp_data_lock(), concurrent softirq

RX processing on another CPU (subflow_data_ready() -> mptcp_data_ready()

-> __mptcp_add_backlog(), under mptcp_data_lock()) could add a backlog

entry referencing the ssk while the cleanup loop was in progress. Such

an entry could be missed by the cleanup, or the concurrent list update

could corrupt the traversal, leaving skb->sk pointing at the ssk after

it is freed.

A later mptcp_backlog_purge() then dereferences the stale pointer,

triggering a warning in inet_sock_destruct() (ssk->sk_rmem_alloc != 0)

followe

Why It Matters

CVE-2026-68170 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.8/10

๐Ÿ›ก๏ธWhat Defenders Should Check

  • Check if you are affected โ€” Review your asset inventory for products listed in CVE-2026-68170.
  • Apply available patches โ€” Visit vendor advisories for the latest security updates.
  • Monitor for exploitation โ€” Check your SIEM/IDS logs for related indicators.
  • Use Vulnios to continuously monitor your exposure to CVE-2026-68170 and similar vulnerabilities.

    References & Sources

    How Vulnios Detects This

    Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.

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    Sources

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    Frequently Asked Questions

    What is CVE-2026-68170?

    CVE-2026-68170 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    mptcp: fix stale skb->sk reference on subflow close

    The backlog list is updated by mptcp_data_ready() under

    mptcp_data_lock(). The

    Am I affected?

    Affected technology is listed in the Affected Products section above. If your asset inventory contains any of them, assume in-scope until you can prove otherwise.

    How urgent is the response?

    Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

    How do I remediate?

    Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

    Where can I track exploitation activity?

    Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2026-68170. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

    How does Vulnios help with this?

    Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.

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