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CVE-2026-64383

Critical Vulnerability: CVE-2026-64383

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced

Monday, July 27, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-64383 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:

smb: client: fix double-free in SMB2_flush() replay

SMB2_flush() keeps its response buffer bookkeeping across replay

attempts. If a replayable flush response is received and the retry then

fails before cifs_send_recv() stores a replacement response, flush_exit

will free the stale response pointer a second time.

Reinitialize resp_buftype and rsp_iov at the top of the replay loop so

cleanup only acts on response state produced by the current attempt.

This fixes a double-free without changing replay handling for successful

requests.

Why It Matters

CVE-2026-64383 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-2026-64383.
  • 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-2026-64383 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-2026-64383?

    CVE-2026-64383 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    smb: client: fix double-free in SMB2_flush() replay

    SMB2_flush() keeps its response buffer bookkeeping across replay

    attempts. If

    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-2026-64383. 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.

    critical

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