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CVE-2026-89969

Critical Vulnerability: CVE-2026-89969

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU nvmet_tcp_try_recv_pdu() reads a PDU header into the fixed 128-byte queue->pdu union, then computes the remaining payload length as queue->left = hdr->hlen - queue->offset + hdgst; and reads that many more bytes into &queue->pdu + queue->offset, without ever bounding the result against sizeof(queue->pdu). A struct nvme_tcp_icreq_pdu is itself 128 bytes, exa

Wednesday, September 16, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-89969 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:

nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU

nvmet_tcp_try_recv_pdu() reads a PDU header into the fixed 128-byte

queue->pdu union, then computes the remaining payload length as

queue->left = hdr->hlen - queue->offset + hdgst;

and reads that many more bytes into &queue->pdu + queue->offset, without

ever bounding the result against sizeof(queue->pdu).

A struct nvme_tcp_icreq_pdu is itself 128 bytes, exactly the size of the

union. Once a header digest has been negotiated (hdgst = 4), a second

ICReq passes the hlen == nvmet_tcp_pdu_size() check but yields

queue->left = 128 - 8 + 4 = 124, so bytes 8..132 are written into the

128-byte buffer -- 4 bytes past its end, over queue->hdr_digest and

queue->data_digest. Those bytes are attacker-controlled (an ICReq

carries no digest), and the duplicate ICReq is only rejected later,

after the overflow. A remote unauthenticated host can thus corrupt

kernel

Why It Matters

CVE-2026-89969 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-2026-89969.
  • 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-2026-89969 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-2026-89969?

    CVE-2026-89969 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: fix out-of-bounds write when receiving an over-long PDU

    nvmet_tcp_try_recv_pdu() reads a PDU header into the fixed 128-

    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-2026-89969. 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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