HighCVE-2026-53359

    Linux Kernel: Use-After-Free (CVE-2026-53359)

    Published Last modified Sources: SUSE, Ubuntu, BSI, Red Hat, Debian, Msrc Update Guide, CVE.org, Debian LTS

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page.

    An exploit is publicly available. Update Linux Kernel to version 5.15.222, Linux Kernel to version 6.1.177, Linux Kernel to version 6.6.144.

    Affected
    • Linux Kernel lt 2.6.36..5.15.222
    • Linux Kernel lt 5.16..6.1.177
    • Linux Kernel lt 6.2..6.6.144
    • Linux Kernel lt 6.7..6.12.95
    • Linux Kernel lt 6.13..6.18.38
    • Linux Kernel lt 6.19..7.1.3
    Fixed in
    • Linux Kernel 5.15.222
    • Linux Kernel 6.1.177
    • Linux Kernel 6.6.144
    • Linux Kernel 6.12.95
    • Linux Kernel 6.18.38
    • Linux Kernel 7.1.3
    • Linux Kernel 7.2

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

    Metrics

    8.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    8.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SUSE, Ubuntu, BSI, Red Hat, Debian, Msrc Update Guide, CVE.org, Debian LTS

    1.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 71.8

    Show all metrics
    Severity
    High
    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
    105.26 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
    PoC (publicly reported)
    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
    8.8 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
    8.8
    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“.

    Read in glossary
    1.4 %
    Moderate — model estimates 1-10% 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
    71.8
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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
    CISA assessment (SSVC)
    Exploitation: proof of concept · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 8 July 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-416

    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
    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: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page. A similar hole however remains if the modified PDE points to a non-leaf page. In this case the gfn can be made to match, but the role does not match: the original large 2MB page creates a kvm_mmu_page with direct=1, while the new 4KB needs a kvm_mmu_page with direct=0. However, kvm_mmu_get_child_sp() does not compare the role, and therefore reuses the page. The next step is installing a leaf (4KB) SPTE on the new path which records an rmap entry under the gfn resolved by the walk. But when that child is zapped its parent kvm_mmu_page has direct=1 and kvm_mmu_page_get_gfn() computes the gfn for the 4KB page as sp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[] in older kernels). It therefore fails to remove the recorded entry. When the memslot is dropped the shadow page is freed but the rmap entry survives, as in the scenario that was already fixed. Code that later walks that gfn (dirty logging, MMU notifier invalidation, and so on) dereferences an sptep that lies in the freed page, causing the use-after-free.

    Source: suse_csaf, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, redhat_csaf, Debian Security Advisories, Microsoft Security Update Guide, cvelistv5, Debian LTS Advisories, NVD (NIST)

    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
    • 5.16 – < 6.1.177
    • 6.7 – < 6.12.95
    • 6.2 – < 6.6.144
    • 2.6.36 – < 5.15.222
    • 6.13 – < 6.18.38
    • —
    • 6.19 – < 7.1.3
    • 6.1.177
    • 6.12.95
    • 6.6.144
    • 5.15.222
    • 6.18.38
    • 7.2
    • 7.1.3
    IBMQRadar SIEM
    • <7.5.0 UP15 IF06
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-oracle-7.0noble
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—
    PoC-in-GitHub (nomi-sec)januscape (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)kvm-kernelcare-januscape (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)almalinux-januscape-mitigation (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-53359 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)LVM-Januscape (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-53359-Kernel-Fix (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)Januscape-Hotfix (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-53359 (opens in a new tab)github.comPoC (publicly reported)reported, not verified
    PoC-in-GitHub (nomi-sec)CVE-2026-53359 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    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 modifiedCVE Program

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/07/06/7
      Referenceremoved
      http://www.openwall.com/lists/oss-security/2026/07/06/7
      —
      Reference typeremoved
      http://www.openwall.com/lists/oss-security/2026/07/06/7 Types: Mailing List
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    2. Record modifiedLinux

      Show 20 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/2026/53xxx/CVE-2026-53359.json">CVE-2026-53359</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/0b5e8ead71e683bcf6232db16234cf7e6d553a23
      Referenceadded
      —
      https://git.kernel.org/stable/c/1ae7d5a6db6c190ce183e3098ca0e0846e14d462
      Referenceadded
      —
      https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35
      Referenceadded
      —
      https://git.kernel.org/stable/c/5e470998a23e4c3d89ed24e8172cb22747e61efa
      Referenceadded
      —
      https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb
      Referenceadded
      —
      https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1
      Referenceadded
      —
      https://git.kernel.org/stable/c/b1337aae5e194324e4810d561764e7793f8b3864
      Referenceremoved
      https://git.kernel.org/stable/c/1ae7d5a6db6c190ce183e3098ca0e0846e14d462
      —
      Referenceremoved
      https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5e470998a23e4c3d89ed24e8172cb22747e61efa
      —
      Referenceremoved
      https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b1337aae5e194324e4810d561764e7793f8b3864
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/1ae7d5a6db6c190ce183e3098ca0e0846e14d462 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5e470998a23e4c3d89ed24e8172cb22747e61efa Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b1337aae5e194324e4810d561764e7793f8b3864 Types: Patch
      —

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

    3. Record modifiedCISA ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/V4bel/Januscape/blob/main/assets/write-up.md
      Referenceremoved
      https://github.com/V4bel/Januscape/blob/main/assets/write-up.md
      —

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Record modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

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

    5. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.2 – before 6.6.144; 6.7 – before 6.12.95; 2.6.36 – before 6.1.177; 6.13 – before 6.18.38; 6.19 – before 7.1.3)

      Weakness type: CWE-416

      Show 9 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.144 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.95 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.36 up to (excluding) 6.1.177 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.38 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.3
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/1ae7d5a6db6c190ce183e3098ca0e0846e14d462 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5e470998a23e4c3d89ed24e8172cb22747e61efa Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/b1337aae5e194324e4810d561764e7793f8b3864 Types: Patch
      Reference typeadded
      —
      CVE: http://www.openwall.com/lists/oss-security/2026/07/06/7 Types: Mailing List

      Source identifier: nvd@nist.gov

    Show 3 older changes

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: proof of concept, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-53359","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-07-07T00:00:00+00:00"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/07/06/7

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. ReceivedLinux

      Description added or changed

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page. A similar hole however remains if the modified PDE points to a non-leaf page. In this case the gfn can be made to match, but the role does not match: the original large 2MB page creates a kvm_mmu_page with direct=1, while the new 4KB needs a kvm_mmu_page with direct=0. However, kvm_mmu_get_child_sp() does not compare the role, and therefore reuses the page. The next step is installing a leaf (4KB) SPTE on the new path which records an rmap entry under the gfn resolved by the walk. But when that child is zapped its parent kvm_mmu_page has direct=1 and kvm_mmu_page_get_gfn() computes the gfn for the 4KB page as sp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[] in older kernels). It therefore fails to remove the recorded entry. When the memslot is dropped the shadow page is freed but the rmap entry survives, as in the scenario that was already fixed. Code that later walks that gfn (dirty logging, MMU notifier invalidation, and so on) dereferences an sptep that lies in the freed page, causing the use-after-free.
      Referenceadded
      —
      https://git.kernel.org/stable/c/1ae7d5a6db6c190ce183e3098ca0e0846e14d462
      Referenceadded
      —
      https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35
      Referenceadded
      —
      https://git.kernel.org/stable/c/5e470998a23e4c3d89ed24e8172cb22747e61efa
      Referenceadded
      —
      https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb
      Referenceadded
      —
      https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1
      Referenceadded
      —
      https://git.kernel.org/stable/c/b1337aae5e194324e4810d561764e7793f8b3864

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

    Linked advisories

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    Badge preview for CVE-2026-53359
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