MediumCVE-2026-99152

    Linux Kernel: NULL Pointer Dereference (CVE-2026-99152)

    Published Last modified Sources: Msrc Update Guide, CVE.org, BSI

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi: Validate the task named by a management response __iscsi_complete_pdu() fetches the task for five response types from one place and checks only that the index resolved: case ISCSI_OP_LOGOUT_RSP: case ISCSI_OP_LOGIN_RSP: case ISCSI_OP_TEXT_RSP: case ISCSI_OP_SCSI_TMFUNC_RSP: case ISCSI_OP_NOOP_IN: task = iscsi_itt_to_task(conn, hdr->itt); if (!task) return ISCSI_ERR_BAD_ITT; iscsi_itt_to_task() bounds the index against cmds_max and looks at nothing else, so a target can name any slot in the pool, including one that has never been used. task->conn is then NULL, and both iscsi_nop_out_rsp() and iscsi_complete_task() dereference it. One unsolicited NOP-In is enough; a Text Response carrying the same ITT crashes in iscsi_complete_task() instead.

    Update Linux Kernel to version 5.10.273, Linux Kernel to version 5.15.224, Linux Kernel to version 6.1.191.

    Affected
    • Linux Kernel lt 2.6.18..5.10.273
    • Linux Kernel lt 5.11..5.15.224
    • Linux Kernel lt 5.16..6.1.191
    • Linux Kernel lt 6.2..6.6.161
    • Linux Kernel lt 6.7..6.12.115
    • Linux Kernel lt 6.13..6.18.59
    • Linux Kernel lt 6.19..7.2.13
    Fixed in
    • Linux Kernel 5.10.273
    • Linux Kernel 5.15.224
    • Linux Kernel 6.1.191
    • Linux Kernel 6.6.161
    • Linux Kernel 6.12.115
    • Linux Kernel 6.18.59
    • Linux Kernel 7.2.13
    • Linux Kernel 7.3

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    Metrics

    5.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Msrc Update Guide, CVE.org, BSI

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 7.5

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    57.95 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.2 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    7.5
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi: Validate the task named by a management response __iscsi_complete_pdu() fetches the task for five response types from one place and checks only that the index resolved: case ISCSI_OP_LOGOUT_RSP: case ISCSI_OP_LOGIN_RSP: case ISCSI_OP_TEXT_RSP: case ISCSI_OP_SCSI_TMFUNC_RSP: case ISCSI_OP_NOOP_IN: task = iscsi_itt_to_task(conn, hdr->itt); if (!task) return ISCSI_ERR_BAD_ITT; iscsi_itt_to_task() bounds the index against cmds_max and looks at nothing else, so a target can name any slot in the pool, including one that has never been used. task->conn is then NULL, and both iscsi_nop_out_rsp() and iscsi_complete_task() dereference it. One unsolicited NOP-In is enough; a Text Response carrying the same ITT crashes in iscsi_complete_task() instead. Require the task to be in flight and not a SCSI command, the way iscsi_itt_to_ctask() does for the command opcodes. [ 6.298634] Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI [ 6.298642] KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] [ 6.298652] CPU: 1 UID: 0 PID: 111 Comm: iscsistart Not tainted 7.2.0-rc5-ISCSI1-gf5098b6bae76 #1 PREEMPT(lazy) [ 6.298654] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 6.298656] RIP: 0010:iscsi_nop_out_rsp.constprop.0+0x46/0x160 [ 6.298691] Code: c1 ea 03 48 83 ec 08 80 3c 02 00 0f 85 f5 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 58 48 8d 7d 60 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c0 00 00 00 48 8b 45 60 48 39 c3 74 50 48 b8 00 [ 6.298698] RSP: 0018:ffff88806c907be8 EFLAGS: 00010206 [ 6.298701] RAX: dffffc0000000000 RBX: ffff888006116800 RCX: 0000000000000020 [ 6.298702] RDX: 000000000000000c RSI: ffff88800525d578 RDI: 0000000000000060 [ 6.298703] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 6.298706] R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000 [ 6.298706] R13: 000000000000002e R14: ffff8880056eb440 R15: ffff888006116800 [ 6.298707] FS: 00007fc02d1c2740(0000) GS:ffff8880b29bc000(0000) knlGS:0000000000000000 [ 6.298710] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6.298711] CR2: 000055fe3b56ddf8 CR3: 00000000053b9004 CR4: 0000000000770ef0 [ 6.298712] PKRU: 55555554 [ 6.298713] Call Trace: [ 6.298714] <IRQ> [ 6.298714] __iscsi_complete_pdu+0x13a8/0x22a0 [ 6.298758] iscsi_complete_pdu+0x54/0xa0 [ 6.298759] iscsi_tcp_hdr_recv_done+0x870/0x2c80 [ 6.298778] iscsi_tcp_recv_skb+0x31e/0xec0 [ 6.298800] iscsi_sw_tcp_recv+0x12f/0x390 [ 6.298804] __tcp_read_sock+0x1ab/0x810 [ 6.298812] iscsi_sw_tcp_data_ready+0x18b/0x510 [ 6.298814] tcp_rcv_established+0x1f56/0x3a00 [ 6.298842] tcp_v4_do_rcv+0x449/0x960 [ 6.298847] tcp_v4_rcv+0x2245/0x3bc0

    Source: Microsoft Security Update Guide, cvelistv5, NVD (NIST), BSI CSAF, BSI WID Portal

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • 6.7 – < 6.12.115
    • 6.19 – < 7.2.13
    • 5.11 – < 5.15.224
    • 5.16 – < 6.1.191
    • 6.13 – < 6.18.59
    • —
    • 6.2 – < 6.6.161
    • 2.6.18 – < 5.10.273
    • 6.12.115
    • 7.2.13
    • 5.15.224
    • 6.1.191
    • 6.18.59
    • 7.3
    • 6.6.161
    • 5.10.273

    Vendors and products

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedLinux

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99152.json">CVE-2026-99152</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/5b56229cc152095fbe4e4ff537cb206c4aa41610
      Referenceadded
      —
      https://git.kernel.org/stable/c/77134cf996bab55683f0ceafb9e300d97ac046f8
      Referenceadded
      —
      https://git.kernel.org/stable/c/7a7a473aec51195778a54fdd71f20fda3047b8ef
      Referenceadded
      —
      https://git.kernel.org/stable/c/bf4035656852a386fecb5d6217710a1bde536e76
      Referenceadded
      —
      https://git.kernel.org/stable/c/e96ae694c5038aae84142b64e41b56324b7af9a7

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    2. ReceivedLinux

      Description added or changed

      Show 5 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi: Validate the task named by a management response __iscsi_complete_pdu() fetches the task for five response types from one place and checks only that the index resolved: case ISCSI_OP_LOGOUT_RSP: case ISCSI_OP_LOGIN_RSP: case ISCSI_OP_TEXT_RSP: case ISCSI_OP_SCSI_TMFUNC_RSP: case ISCSI_OP_NOOP_IN: task = iscsi_itt_to_task(conn, hdr->itt); if (!task) return ISCSI_ERR_BAD_ITT; iscsi_itt_to_task() bounds the index against cmds_max and looks at nothing else, so a target can name any slot in the pool, including one that has never been used. task->conn is then NULL, and both iscsi_nop_out_rsp() and iscsi_complete_task() dereference it. One unsolicited NOP-In is enough; a Text Response carrying the same ITT crashes in iscsi_complete_task() instead. Require the task to be in flight and not a SCSI command, the way iscsi_itt_to_ctask() does for the command opcodes. [ 6.298634] Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI [ 6.298642] KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] [ 6.298652] CPU: 1 UID: 0 PID: 111 Comm: iscsistart Not tainted 7.2.0-rc5-ISCSI1-gf5098b6bae76 #1 PREEMPT(lazy) [ 6.298654] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 6.298656] RIP: 0010:iscsi_nop_out_rsp.constprop.0+0x46/0x160 [ 6.298691] Code: c1 ea 03 48 83 ec 08 80 3c 02 00 0f 85 f5 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 58 48 8d 7d 60 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c0 00 00 00 48 8b 45 60 48 39 c3 74 50 48 b8 00 [ 6.298698] RSP: 0018:ffff88806c907be8 EFLAGS: 00010206 [ 6.298701] RAX: dffffc0000000000 RBX: ffff888006116800 RCX: 0000000000000020 [ 6.298702] RDX: 000000000000000c RSI: ffff88800525d578 RDI: 0000000000000060 [ 6.298703] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 6.298706] R10: 0000000000000020 R11: 0000000000000000 R12: 0000000000000000 [ 6.298706] R13: 000000000000002e R14: ffff8880056eb440 R15: ffff888006116800 [ 6.298707] FS: 00007fc02d1c2740(0000) GS:ffff8880b29bc000(0000) knlGS:0000000000000000 [ 6.298710] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6.298711] CR2: 000055fe3b56ddf8 CR3: 00000000053b9004 CR4: 0000000000770ef0 [ 6.298712] PKRU: 55555554 [ 6.298713] Call Trace: [ 6.298714] <IRQ> [ 6.298714] __iscsi_complete_pdu+0x13a8/0x22a0 [ 6.298758] iscsi_complete_pdu+0x54/0xa0 [ 6.298759] iscsi_tcp_hdr_recv_done+0x870/0x2c80 [ 6.298778] iscsi_tcp_recv_skb+0x31e/0xec0 [ 6.298800] iscsi_sw_tcp_recv+0x12f/0x390 [ 6.298804] __tcp_read_sock+0x1ab/0x810 [ 6.298812] iscsi_sw_tcp_data_ready+0x18b/0x510 [ 6.298814] tcp_rcv_established+0x1f56/0x3a00 [ 6.298842] tcp_v4_do_rcv+0x449/0x960 [ 6.298847] tcp_v4_rcv+0x2245/0x3bc0
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99152.json">CVE-2026-99152</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/11bffcd9cb346732eab2914ef44fe777a3f0b585
      Referenceadded
      —
      https://git.kernel.org/stable/c/55a65ef61e2775aeb18fda63bd1959fa8b41f936
      Referenceadded
      —
      https://git.kernel.org/stable/c/f721487523d45941aed4b0ac8d829b0461a7d860

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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