Common Weakness Enumeration

CWE-416

Allowed

Use After Free

Abstraction: Variant · Status: Stable

API response cwe.mitre.org

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

9868 vulnerabilities reference this CWE, most recent first.

GHSA-G7R5-HM7J-WQQ8

Vulnerability from github – Published: 2023-08-10 15:30 – Updated: 2024-04-04 06:48
VLAI
Details

Adobe Acrobat Reader versions 23.003.20244 (and earlier) and 20.005.30467 (and earlier) are affected by a Use-After-Free vulnerability that could lead to disclosure of sensitive memory. An attacker could leverage this vulnerability to bypass mitigations such as ASLR. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2023-38238"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-08-10T14:15:13Z",
    "severity": "MODERATE"
  },
  "details": "Adobe Acrobat Reader versions 23.003.20244 (and earlier) and 20.005.30467 (and earlier) are affected by a Use-After-Free vulnerability that could lead to disclosure of sensitive memory. An attacker could leverage this vulnerability to bypass mitigations such as ASLR. Exploitation of this issue requires user interaction in that a victim must open a malicious file.",
  "id": "GHSA-g7r5-hm7j-wqq8",
  "modified": "2024-04-04T06:48:00Z",
  "published": "2023-08-10T15:30:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-38238"
    },
    {
      "type": "WEB",
      "url": "https://helpx.adobe.com/security/products/acrobat/apsb23-30.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G7X6-Q2CP-CFQW

Vulnerability from github – Published: 2026-05-19 06:30 – Updated: 2026-05-19 06:30
VLAI
Details

in OpenHarmony v6.0 and prior versions allow a local attacker arbitrary code execution.

Severity
6.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-28733"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-19T04:16:30Z",
    "severity": "MODERATE"
  },
  "details": "in OpenHarmony v6.0 and prior versions allow a local attacker arbitrary code execution.",
  "id": "GHSA-g7x6-q2cp-cfqw",
  "modified": "2026-05-19T06:30:30Z",
  "published": "2026-05-19T06:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28733"
    },
    {
      "type": "WEB",
      "url": "https://gitcode.com/openharmony/security/tree/master/zh/security-disclosure/2026/2026-05.md"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G7XX-957C-2XF3

Vulnerability from github – Published: 2024-04-02 21:30 – Updated: 2024-04-02 21:30
VLAI
Details

Foxit PDF Reader AcroForm Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit PDF Reader. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the handling of Acroforms. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-22706.

Severity
7.8 (High)
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-30339"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-04-02T20:15:10Z",
    "severity": "HIGH"
  },
  "details": "Foxit PDF Reader AcroForm Use-After-Free Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit PDF Reader. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.\n\nThe specific flaw exists within the handling of Acroforms. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-22706.",
  "id": "GHSA-g7xx-957c-2xf3",
  "modified": "2024-04-02T21:30:27Z",
  "published": "2024-04-02T21:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-30339"
    },
    {
      "type": "WEB",
      "url": "https://www.foxit.com/support/security-bulletins.html"
    },
    {
      "type": "WEB",
      "url": "https://www.zerodayinitiative.com/advisories/ZDI-24-317"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G846-CH2F-GJ27

Vulnerability from github – Published: 2022-05-12 00:00 – Updated: 2022-05-12 00:00
VLAI
Details

Acrobat Reader DC versions 22.001.20085 (and earlier), 20.005.3031x (and earlier) and 17.012.30205 (and earlier) are affected by a use-after-free vulnerability in the processing of the acroform event that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2022-27799"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2022-05-11T18:15:00Z",
    "severity": "HIGH"
  },
  "details": "Acrobat Reader DC versions 22.001.20085 (and earlier), 20.005.3031x (and earlier) and 17.012.30205 (and earlier) are affected by a use-after-free vulnerability in the processing of the acroform event that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.",
  "id": "GHSA-g846-ch2f-gj27",
  "modified": "2022-05-12T00:00:42Z",
  "published": "2022-05-12T00:00:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-27799"
    },
    {
      "type": "WEB",
      "url": "https://helpx.adobe.com/security/products/acrobat/apsb22-16.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G84C-P3CX-4MCW

Vulnerability from github – Published: 2022-05-13 01:34 – Updated: 2022-05-13 01:34
VLAI
Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.5096. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the processing of FileAttachment annotations. By manipulating a document's elements an attacker can cause a pointer to be reused after it has been freed. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-6211.

Severity
8.8 (High)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2018-14294"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2018-07-31T20:29:00Z",
    "severity": "HIGH"
  },
  "details": "This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.0.1.5096. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the processing of FileAttachment annotations. By manipulating a document\u0027s elements an attacker can cause a pointer to be reused after it has been freed. An attacker can leverage this vulnerability to execute code under the context of the current process. Was ZDI-CAN-6211.",
  "id": "GHSA-g84c-p3cx-4mcw",
  "modified": "2022-05-13T01:34:35Z",
  "published": "2022-05-13T01:34:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-14294"
    },
    {
      "type": "WEB",
      "url": "https://www.foxitsoftware.com/support/security-bulletins.php"
    },
    {
      "type": "WEB",
      "url": "https://zerodayinitiative.com/advisories/ZDI-18-754"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G87F-XJ4Q-8QWQ

Vulnerability from github – Published: 2026-06-05 00:31 – Updated: 2026-06-05 03:31
VLAI
Details

Use after free in Viz in Google Chrome prior to 149.0.7827.53 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page. (Chromium security severity: High)

Severity
8.3 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-10918"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-04T23:16:53Z",
    "severity": "HIGH"
  },
  "details": "Use after free in Viz in Google Chrome prior to 149.0.7827.53 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page. (Chromium security severity: High)",
  "id": "GHSA-g87f-xj4q-8qwq",
  "modified": "2026-06-05T03:31:31Z",
  "published": "2026-06-05T00:31:38Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-10918"
    },
    {
      "type": "WEB",
      "url": "https://chromereleases.googleblog.com/2026/06/stable-channel-update-for-desktop.html"
    },
    {
      "type": "WEB",
      "url": "https://issues.chromium.org/issues/498259721"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G87R-23VW-7F87

Vulnerability from github – Published: 2022-01-06 22:00 – Updated: 2022-01-06 20:20
VLAI
Summary
Use After Free in rusqlite
Details

An issue was discovered in the rusqlite crate 0.25.x before 0.25.4 and 0.26.x before 0.26.2 for Rust. update_hook has a use-after-free.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "rusqlite"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.25.0"
            },
            {
              "fixed": "0.25.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "rusqlite"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.26.0"
            },
            {
              "fixed": "0.26.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-45719"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-01-05T21:01:21Z",
    "nvd_published_at": "2021-12-26T22:15:00Z",
    "severity": "HIGH"
  },
  "details": "An issue was discovered in the rusqlite crate 0.25.x before 0.25.4 and 0.26.x before 0.26.2 for Rust. update_hook has a use-after-free.",
  "id": "GHSA-g87r-23vw-7f87",
  "modified": "2022-01-06T20:20:42Z",
  "published": "2022-01-06T22:00:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-45719"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rusqlite/rusqlite/issues/1048"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rusqlite/rusqlite"
    },
    {
      "type": "WEB",
      "url": "https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/rusqlite/RUSTSEC-2021-0128.md"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2021-0128.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Use After Free in rusqlite"
}

GHSA-G8FV-R98J-937R

Vulnerability from github – Published: 2025-03-14 03:31 – Updated: 2025-11-03 21:33
VLAI
Details

xsltGetInheritedNsList in libxslt before 1.1.43 has a use-after-free issue related to exclusion of result prefixes.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2024-55549"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-03-14T02:15:15Z",
    "severity": "HIGH"
  },
  "details": "xsltGetInheritedNsList in libxslt before 1.1.43 has a use-after-free issue related to exclusion of result prefixes.",
  "id": "GHSA-g8fv-r98j-937r",
  "modified": "2025-11-03T21:33:11Z",
  "published": "2025-03-14T03:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-55549"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/libxslt/-/issues/127"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00015.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G8G5-F7QQ-6H9M

Vulnerability from github – Published: 2022-05-24 17:48 – Updated: 2025-10-22 00:32
VLAI
Details

Use after free in Blink in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2021-21206"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-04-26T17:15:00Z",
    "severity": "HIGH"
  },
  "details": "Use after free in Blink in Google Chrome prior to 89.0.4389.128 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.",
  "id": "GHSA-g8g5-f7qq-6h9m",
  "modified": "2025-10-22T00:32:07Z",
  "published": "2022-05-24T17:48:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21206"
    },
    {
      "type": "WEB",
      "url": "https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop.html"
    },
    {
      "type": "WEB",
      "url": "https://crbug.com/1196781"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202104-08"
    },
    {
      "type": "WEB",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21206"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-G8Q5-FWJH-4Q25

Vulnerability from github – Published: 2026-04-24 15:32 – Updated: 2026-06-01 18:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Use scratch field in MMIO fragment to hold small write values

When exiting to userspace to service an emulated MMIO write, copy the to-be-written value to a scratch field in the MMIO fragment if the size of the data payload is 8 bytes or less, i.e. can fit in a single chunk, instead of pointing the fragment directly at the source value.

This fixes a class of use-after-free bugs that occur when the emulator initiates a write using an on-stack, local variable as the source, the write splits a page boundary, and both pages are MMIO pages. Because KVM's ABI only allows for physically contiguous MMIO requests, accesses that split MMIO pages are separated into two fragments, and are sent to userspace one at a time. When KVM attempts to complete userspace MMIO in response to KVM_RUN after the first fragment, KVM will detect the second fragment and generate a second userspace exit, and reference the on-stack variable.

The issue is most visible if the second KVM_RUN is performed by a separate task, in which case the stack of the initiating task can show up as truly freed data.

================================================================== BUG: KASAN: use-after-free in complete_emulated_mmio+0x305/0x420 Read of size 1 at addr ffff888009c378d1 by task syz-executor417/984

CPU: 1 PID: 984 Comm: syz-executor417 Not tainted 5.10.0-182.0.0.95.h2627.eulerosv2r13.x86_64 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0xbe/0xfd print_address_description.constprop.0+0x19/0x170 __kasan_report.cold+0x6c/0x84 kasan_report+0x3a/0x50 check_memory_region+0xfd/0x1f0 memcpy+0x20/0x60 complete_emulated_mmio+0x305/0x420 kvm_arch_vcpu_ioctl_run+0x63f/0x6d0 kvm_vcpu_ioctl+0x413/0xb20 __se_sys_ioctl+0x111/0x160 do_syscall_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1 RIP: 0033:0x42477d Code: <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007faa8e6890e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004d7338 RCX: 000000000042477d RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00000000004d7330 R08: 00007fff28d546df R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004d733c R13: 0000000000000000 R14: 000000000040a200 R15: 00007fff28d54720

The buggy address belongs to the page: page:0000000029f6a428 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9c37 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffea0000270dc8 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff888009c37780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888009c37800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

ffff888009c37880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888009c37900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888009c37980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================

The bug can also be reproduced with a targeted KVM-Unit-Test by hacking KVM to fill a large on-stack variable in complete_emulated_mmio(), i.e. by overwrite the data value with garbage.

Limit the use of the scratch fields to 8-byte or smaller accesses, and to just writes, as larger accesses and reads are not affected thanks to implementation details in the emulator, but add a sanity check to ensure those details don't change in the future. Specifically, KVM never uses on-stack variables for accesses larger that 8 bytes, e.g. uses an operand in the emulator context, and *al ---truncated---

Severity
8.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-31588"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-24T15:16:33Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Use scratch field in MMIO fragment to hold small write values\n\nWhen exiting to userspace to service an emulated MMIO write, copy the\nto-be-written value to a scratch field in the MMIO fragment if the size\nof the data payload is 8 bytes or less, i.e. can fit in a single chunk,\ninstead of pointing the fragment directly at the source value.\n\nThis fixes a class of use-after-free bugs that occur when the emulator\ninitiates a write using an on-stack, local variable as the source, the\nwrite splits a page boundary, *and* both pages are MMIO pages.  Because\nKVM\u0027s ABI only allows for physically contiguous MMIO requests, accesses\nthat split MMIO pages are separated into two fragments, and are sent to\nuserspace one at a time.  When KVM attempts to complete userspace MMIO in\nresponse to KVM_RUN after the first fragment, KVM will detect the second\nfragment and generate a second userspace exit, and reference the on-stack\nvariable.\n\nThe issue is most visible if the second KVM_RUN is performed by a separate\ntask, in which case the stack of the initiating task can show up as truly\nfreed data.\n\n  ==================================================================\n  BUG: KASAN: use-after-free in complete_emulated_mmio+0x305/0x420\n  Read of size 1 at addr ffff888009c378d1 by task syz-executor417/984\n\n  CPU: 1 PID: 984 Comm: syz-executor417 Not tainted 5.10.0-182.0.0.95.h2627.eulerosv2r13.x86_64 #3\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 Call Trace:\n  dump_stack+0xbe/0xfd\n  print_address_description.constprop.0+0x19/0x170\n  __kasan_report.cold+0x6c/0x84\n  kasan_report+0x3a/0x50\n  check_memory_region+0xfd/0x1f0\n  memcpy+0x20/0x60\n  complete_emulated_mmio+0x305/0x420\n  kvm_arch_vcpu_ioctl_run+0x63f/0x6d0\n  kvm_vcpu_ioctl+0x413/0xb20\n  __se_sys_ioctl+0x111/0x160\n  do_syscall_64+0x30/0x40\n  entry_SYSCALL_64_after_hwframe+0x67/0xd1\n  RIP: 0033:0x42477d\n  Code: \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48\n  RSP: 002b:00007faa8e6890e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n  RAX: ffffffffffffffda RBX: 00000000004d7338 RCX: 000000000042477d\n  RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005\n  RBP: 00000000004d7330 R08: 00007fff28d546df R09: 0000000000000000\n  R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004d733c\n  R13: 0000000000000000 R14: 000000000040a200 R15: 00007fff28d54720\n\n  The buggy address belongs to the page:\n  page:0000000029f6a428 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9c37\n  flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)\n  raw: 000fffffc0000000 0000000000000000 ffffea0000270dc8 0000000000000000\n  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected\n\n  Memory state around the buggy address:\n  ffff888009c37780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n  ffff888009c37800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n  \u003effff888009c37880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n                                                   ^\n  ffff888009c37900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n  ffff888009c37980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff\n  ==================================================================\n\nThe bug can also be reproduced with a targeted KVM-Unit-Test by hacking\nKVM to fill a large on-stack variable in complete_emulated_mmio(), i.e. by\noverwrite the data value with garbage.\n\nLimit the use of the scratch fields to 8-byte or smaller accesses, and to\njust writes, as larger accesses and reads are not affected thanks to\nimplementation details in the emulator, but add a sanity check to ensure\nthose details don\u0027t change in the future.  Specifically, KVM never uses\non-stack variables for accesses larger that 8 bytes, e.g. uses an operand\nin the emulator context, and *al\n---truncated---",
  "id": "GHSA-g8q5-fwjh-4q25",
  "modified": "2026-06-01T18:31:26Z",
  "published": "2026-04-24T15:32:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31588"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/019d0bd32b9a4646ba35d904907452039e2db700"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0b16e69d17d8c35c5c9d5918bf596c75a44655d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22d2ff69d487a32a8b88f9c970120fc2daa08a77"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b83d91e9ae92fe1258d7040a32430bbb3bb7d6e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a7b6d75c8f85b09dea893f64a85a356bcf6c3fe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4569c66dd9e94a22cd0796b6514a8b25ffff16a1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52570e73d48f1c73836d37e594667117b4c2a5a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b5a02d37eb0739f462fa12df449ab9b3480c783b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc6a6c3db3a4eca7e747cfc46e22c08d016c68f7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}
Mitigation
Architecture and Design

Strategy: Language Selection

Choose a language that provides automatic memory management.

Mitigation
Implementation

Strategy: Attack Surface Reduction

When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

No CAPEC attack patterns related to this CWE.

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