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CVE-2026-64541

Critical Vulnerability: CVE-2026-64541

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket smc_cdc_rx_handler() looks up the connection by token under the link group's conns_lock, drops the lock, and then dereferences conn and the smc_sock derived from it, ending in sock_hold(&smc->sk) inside smc_cdc_msg_recv(). No reference is held across the lock release. The only reference pinning the socket while the connection is discoverable in the link group is t

Thursday, July 30, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-64541 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:

net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket

smc_cdc_rx_handler() looks up the connection by token under the link

group's conns_lock, drops the lock, and then dereferences conn and the

smc_sock derived from it, ending in sock_hold(&smc->sk) inside

smc_cdc_msg_recv(). No reference is held across the lock release.

The only reference pinning the socket while the connection is

discoverable in the link group is taken in smc_lgr_register_conn()

(sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both

under conns_lock. Once the handler drops conns_lock, a concurrent

close() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn()

can drop that reference and free the smc_sock, so the handler's later

sock_hold() runs on freed memory:

WARNING: lib/refcount.c:25 at refcount_warn_saturate

Workqueue: rxe_wq do_work

refcount_warn_saturate (lib/refcount.c:25)

smc_cdc_msg_recv (ne

Why It Matters

CVE-2026-64541 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.8/10

EPSS (Exploit Prediction): 0.2% probability of exploitation in the next 30 days.

๐Ÿ›ก๏ธWhat Defenders Should Check

  • Check if you are affected โ€” Review your asset inventory for products listed in CVE-2026-64541.
  • 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-2026-64541 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

    Related Threat Alerts

    Frequently Asked Questions

    What is CVE-2026-64541?

    CVE-2026-64541 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket

    smc_cdc_rx_handler() looks up the connection by token under the lin

    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-2026-64541. 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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