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CVE-2026-99154

Critical Vulnerability: CVE-2026-99154

In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi: Reject a negative task index from parse_pdu_itt A transport that implements parse_pdu_itt hands libiscsi an index taken from the PDU, and both lookups bound it from above only: if (i >= session->cmds_max) i and cmds_max are both int, so a negative index passes and session->cmds[i] is read from before the array. be2iscsi produces one. beiscsi_parse_pdu() assigns the raw tag, *index = (int)itt; a

Saturday, October 31, 2026Vulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2026-99154 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:

scsi: libiscsi: Reject a negative task index from parse_pdu_itt

A transport that implements parse_pdu_itt hands libiscsi an index taken

from the PDU, and both lookups bound it from above only:

if (i >= session->cmds_max)

i and cmds_max are both int, so a negative index passes and

session->cmds[i] is read from before the array.

be2iscsi produces one. beiscsi_parse_pdu() assigns the raw tag,

*index = (int)itt;

and beiscsi_complete_pdu() forwards an unsolicited NOP-In from the

hardware async ring without replacing its ITT, so the value is the

target's. It also reports the session's own age rather than the one in

the tag, which leaves the age comparison in iscsi_verify_itt() with

nothing to reject.

Bound the index from below in both lookups.

Why It Matters

CVE-2026-99154 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.

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2026-99154.
  • 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-2026-99154 and similar vulnerabilities.

    References & Sources

  • https://git.kernel.org/stable/c/0eb06ebbbecb122f0df9a1f7f623f5255be741ed
  • https://git.kernel.org/stable/c/24bd9ba431b2daa263f3551bc2f09f6b4487f5ae
  • https://git.kernel.org/stable/c/35b60549a956237488c89a2d85352e026e7d55b7
  • https://git.kernel.org/stable/c/6200fb2de579f268742a77b0f3d823cb0a8b1947
  • https://git.kernel.org/stable/c/6cadfa6f1f5896632d4223d3b7addb2a29fea74e
  • https://git.kernel.org/stable/c/8ee2a09a1dbb257c9e828ad2497f8e4832dfb142
  • https://git.kernel.org/stable/c/e896a97f336c5edfc13066b57ed431cb3f64e68c
  • https://git.kernel.org/stable/c/f8fabe1fe044f86abc42194b8f86dfd70212115f

    • 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-2026-99154?

    CVE-2026-99154 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. In the Linux kernel, the following vulnerability has been resolved:

    scsi: libiscsi: Reject a negative task index from parse_pdu_itt

    A transport that implements parse_pdu_itt hands libiscsi an index

    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-2026-99154. 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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