VulnerabilityPublished 28 Oct 2026Updated 30 Oct 2026

CVE-2026-99154: Linux kernel · scsi: libiscsi: Reject a negative task index from parse_pdu_itt

Affects Linux kernelSource GCVE Database

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Authoritative record:CVE-2026-99154· Medium

Not known to be exploited.

Data as of 30 Oct 2026, 03:51 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10linux`pkg:deb/ubuntu/linux?arch=source&distro=stonking`Other threats	Affected 7.0.0-14.14 – 7.3.0-10.10 7 affected builds	Fixed in–
Ubuntu 26.10linux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1004.4 6 affected builds	Fixed in–
Ubuntu 26.10linux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1004.4 6 affected builds	Fixed in–
Ubuntu 26.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1004.5 4 affected builds	Fixed in–
Ubuntu 26.10linux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1004.4 6 affected builds	Fixed in–
Ubuntu 26.10linux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1004.4 6 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by adding lower bound checks on the task index in parse_pdu_itt and related lookups. Users should update affected Linux kernel versions to the fixed releases to mitigate this issue. No additional mitigations are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's libiscsi SCSI transport allows a negative task index to be used in parse_pdu_itt, leading to an out-of-bounds read from the session command array. This occurs because the index is only bounded from above, not below, permitting negative values to access memory before the array. The issue is related to how beiscsi handles unsolicited NOP-In PDUs and the session age comparison, which fails to reject invalid indices. This flaw has been resolved by adding a lower bound check on the index in both lookups.

Impact

This vulnerability allows an attacker to cause out-of-bounds reads in the kernel memory via crafted SCSI PDUs, potentially leading to information disclosure or kernel instability. However, no known exploits in the wild have been reported. The impact is considered medium severity due to the possibility of memory corruption or information leakage but no direct code execution or privilege escalation has been documented.

Summary

The Linux kernel's libiscsi SCSI transport had a vulnerability where parse_pdu_itt accepted a negative task index derived from the PDU without proper lower bound checking. Since the index and cmds_max were both signed integers, negative indices passed the upper bound check and caused out-of-bounds reads from the session->cmds array. The beiscsi driver contributed to this issue by forwarding unsolicited NOP-In PDUs with raw tags that were not sanitized, and by reporting the session's own age rather than the tag's age, which disabled rejection in iscsi_verify_itt. The fix involved bounding the index from below to prevent negative values from being used.

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2026-99154
Osv Schema Version: 1.7.0
Ecosystems: Ubuntu:Pro:14.04:LTS, Ubuntu:Pro:16.04:LTS, Ubuntu:16.04:LTS, Ubuntu:Pro:FIPS-updates:16.04:LTS, Ubuntu:Pro:FIPS:16.04:LTS, Ubuntu:Pro:18.04:LTS, Ubuntu:18.04:LTS, Ubuntu:Pro:FIPS-updates:18.04:LTS, Ubuntu:Pro:FIPS:18.04:LTS, Ubuntu:Pro:20.04:LTS, Ubuntu:20.04:LTS, Ubuntu:Pro:FIPS-updates:20.04:LTS, Ubuntu:Pro:FIPS:20.04:LTS, Ubuntu:22.04:LTS, Ubuntu:Nvidia-BlueField:22.04:LTS, Ubuntu:Pro:Realtime:22.04:LTS, Ubuntu:Pro:FIPS-preview:22.04:LTS, Ubuntu:Pro:FIPS-updates:22.04:LTS, Ubuntu:24.04:LTS, Ubuntu:Nvidia-BlueField:24.04:LTS, Ubuntu:Pro:Realtime:24.04:LTS, Ubuntu:Pro:FIPS-updates:24.04:LTS, Ubuntu:26.10, Ubuntu:26.04:LTS

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What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 03:51 UTC

Technical details

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