HighCVE-2026-90205

    Linux Kernel: Use-After-Free (CVE-2026-90205)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate orphan slot during inode read Patch series "ocfs2: validate active orphan slots during inode read". OCFS2 trusts active ordinary and append-DIO orphan slots read from dinodes.

    Update Linux Kernel to version 6.18.52, Linux Kernel to version 7.2.6, Linux Kernel to version 7.3.

    Affected
    • Linux Kernel lt 2.6.16..6.18.52
    • Linux Kernel lt 6.19..7.2.6
    Fixed in
    • Linux Kernel 6.18.52
    • Linux Kernel 7.2.6
    • Linux Kernel 7.3

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org, Msrc Update Guide, BSI

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 7.0

    Show all metrics
    Severity
    High
    Priority score

    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
    68.82
    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
    7.8
    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
    7.8
    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“.

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    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.

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    7.0
    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.

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    —
    Published

    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
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    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: ocfs2: validate orphan slot during inode read Patch series "ocfs2: validate active orphan slots during inode read". OCFS2 trusts active ordinary and append-DIO orphan slots read from dinodes. A corrupted slot can therefore index osb_orphan_wipes or the slot-local system-inode cache outside their allocations before the corruption is reported. Patch 1 validates the ordinary orphan slot used by inode wipe processing. Patch 2 validates the append-DIO orphan slot used by DIO completion and orphan recovery. Both checks reject corrupt metadata at the existing inode validation boundary. This patch (of 2): [BUG] A corrupted dinode with OCFS2_ORPHANED_FL can carry an i_orphaned_slot outside the mounted filesystem slot range. ocfs2_wipe_inode() uses it to index osb_orphan_wipes before looking up the orphan directory, causing an out-of-bounds memory access. BUG: KASAN: slab-use-after-free in ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 Read of size 8 at addr ffff88800b767c00 by task kworker/u8:3/85 Call Trace: ... ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 ocfs2_wipe_inode+0x292/0xf70 fs/ocfs2/inode.c:840 ocfs2_delete_inode fs/ocfs2/inode.c:1155 [inline] ocfs2_evict_inode+0x6c9/0x1170 fs/ocfs2/inode.c:1295 evict+0x38e/0x8f0 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput fs/inode.c:1966 [inline] iput+0x55b/0x8b0 fs/inode.c:1926 ocfs2_recover_orphans+0x610/0xe40 fs/ocfs2/journal.c:2374 ocfs2_complete_recovery+0x5af/0xd00 fs/ocfs2/journal.c:1373 ... [CAUSE] ocfs2_validate_inode_block() validates i_suballoc_slot but leaves the active ordinary orphan slot unchecked. Downstream consumers assume that the value is smaller than osb->max_slots. [FIX] Reject an active i_orphaned_slot outside the slot range during dinode validation, before the inode reaches orphan wipe processing.

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

    Affected products

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

    Affected products
    VendorProductAffected versionsFixed in
    LinuxLinux
    • 2.6.16 – < 6.18.52
    • 6.19 – < 7.2.6
    • —
    • 6.18.52
    • 7.2.6
    • 7.3

    References & sources

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. CVE Modified416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90205.json">CVE-2026-90205</a>

    2. CVE Modified416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • CVSS V3.1: after AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

    3. New CVE Received416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • Description: after In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate orphan slot during inode read Patch series "ocfs2: validate active orphan slots during inode read". OCFS2 trusts active ordinary and append-DIO orphan slots read from dinodes. A corrupted slot can therefore index osb_orphan_wipes or the slot-local system-inode cache outside their allocations before the corruption is reported. Patch 1 validates the ordinary orphan slot used by inode wipe processing. Patch 2 validates the append-DIO orphan slot used by DIO completion and orphan recovery. Both checks reject corrupt metadata at the existing inode validation boundary. This patch (of 2): [BUG] A corrupted dinode with OCFS2_ORPHANED_FL can carry an i_orphaned_slot outside the mounted filesystem slot range. ocfs2_wipe_inode() uses it to index osb_orphan_wipes before looking up the orphan directory, causing an out-of-bounds memory access. BUG: KASAN: slab-use-after-free in ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 Read of size 8 at addr ffff88800b767c00 by task kworker/u8:3/85 Call Trace: ... ocfs2_get_system_file_inode+0x780/0x820 fs/ocfs2/sysfile.c:102 ocfs2_wipe_inode+0x292/0xf70 fs/ocfs2/inode.c:840 ocfs2_delete_inode fs/ocfs2/inode.c:1155 [inline] ocfs2_evict_inode+0x6c9/0x1170 fs/ocfs2/inode.c:1295 evict+0x38e/0x8f0 fs/inode.c:810 iput_final fs/inode.c:1914 [inline] iput fs/inode.c:1966 [inline] iput+0x55b/0x8b0 fs/inode.c:1926 ocfs2_recover_orphans+0x610/0xe40 fs/ocfs2/journal.c:2374 ocfs2_complete_recovery+0x5af/0xd00 fs/ocfs2/journal.c:1373 ... [CAUSE] ocfs2_validate_inode_block() validates i_suballoc_slot but leaves the active ordinary orphan slot unchecked. Downstream consumers assume that the value is smaller than osb->max_slots. [FIX] Reject an active i_orphaned_slot outside the slot range during dinode validation, before the inode reaches orphan wipe processing.
      • Affected: after New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90205.json">CVE-2026-90205</a>
      • Reference: after https://git.kernel.org/stable/c/3d7c4b7ce7b4baedfd8699fa692cd95f77d332de
      • Reference: after https://git.kernel.org/stable/c/b2d31acbd3b182755b019183fb46949ba5e39b9f