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CVE-2026-52989

Critical Vulnerability: CVE-2026-52989

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers Currently, when nvmet_tcp_build_pdu_iovec() detects an out-of-bounds PDU length or offset, it triggers nvmet_tcp_fatal_error(cmd->queue) and returns early. However, because the function returns void, the callers are entirely unaware that a fatal error has occurred and that the cmd->recv_msg.msg_iter was left uninitialized. Callers such as nvmet_tcp_handle_

Tuesday, June 30, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-52989 is rated CRITICAL — 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:

nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers

Currently, when nvmet_tcp_build_pdu_iovec() detects an out-of-bounds

PDU length or offset, it triggers nvmet_tcp_fatal_error(cmd->queue)

and returns early. However, because the function returns void, the

callers are entirely unaware that a fatal error has occurred and

that the cmd->recv_msg.msg_iter was left uninitialized.

Callers such as nvmet_tcp_handle_h2c_data_pdu() proceed to blindly

overwrite the queue state with queue->rcv_state = NVMET_TCP_RECV_DATA

Consequently, the socket receiving loop may attempt to read incoming

network data into the uninitialized iterator.

Fix this by shifting the error handling responsibility to the callers.

Why It Matters

CVE-2026-52989 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9.8/10

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2026-52989.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

    • Use Vulnios to continuously monitor your exposure to CVE-2026-52989 and similar vulnerabilities.

    References & Sources

  • https://git.kernel.org/stable/c/046fa5c72d15cd8e2d592e275697ea399d8f76b0
  • https://git.kernel.org/stable/c/3df42a854686fa06484e37ac1a3931c8e3e3453c
  • https://git.kernel.org/stable/c/c2a11441538bdbbc5aa003f190995eba93a89b88
  • https://git.kernel.org/stable/c/d7c8f95f599b3b38a717d2e771c3f8c174f657c3
  • https://git.kernel.org/stable/c/ea8e356acb165cb1fd75537a52e1f66e5e76c538
  • https://git.kernel.org/stable/c/f9204a2b78dd18374d3bcf9bf93d9021ce22de1b
  • https://access.redhat.com/security/cve/CVE-2026-52989
  • https://bugzilla.redhat.com/show_bug.cgi?id=2492443
  • https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52989.json

    • 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-2026-52989?

    CVE-2026-52989 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers

    Currently, when nvmet_tcp_build_pdu_iovec() detects an out-

    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-2026-52989. 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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