Vulnerability-Lookup

FKIE_CVE-2026-43249

Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-06-17 10:49

Severity

8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: 9p/xen: protect xen_9pfs_front_free against concurrent calls The xenwatch thread can race with other back-end change notifications and call xen_9pfs_front_free() twice, hitting the observed general protection fault due to a double-free. Guard the teardown path so only one caller can release the front-end state at a time, preventing the crash. This is a fix for the following double-free: [ 27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none) [ 27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150 [ 27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 <48> 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42 [ 27.052377] RSP: e02b:ffffc9004016fdd0 EFLAGS: 00010246 [ 27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX: 0000000000000000 [ 27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000 [ 27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000 [ 27.052393] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68 [ 27.052397] R13: 0000000000000200 R14: 0000000000000000 R15: ffff88800a887040 [ 27.052404] FS: 0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000 [ 27.052408] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.052412] CR2: 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660 [ 27.052418] Call Trace: [ 27.052420] <TASK> [ 27.052422] xen_9pfs_front_changed+0x5d5/0x720 [ 27.052426] ? xenbus_otherend_changed+0x72/0x140 [ 27.052430] ? __pfx_xenwatch_thread+0x10/0x10 [ 27.052434] xenwatch_thread+0x94/0x1c0 [ 27.052438] ? __pfx_autoremove_wake_function+0x10/0x10 [ 27.052442] kthread+0xf8/0x240 [ 27.052445] ? __pfx_kthread+0x10/0x10 [ 27.052449] ? __pfx_kthread+0x10/0x10 [ 27.052452] ret_from_fork+0x16b/0x1a0 [ 27.052456] ? __pfx_kthread+0x10/0x10 [ 27.052459] ret_from_fork_asm+0x1a/0x30 [ 27.052463] </TASK> [ 27.052465] Modules linked in: [ 27.052471] ---[ end trace 0000000000000000 ]---

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/59e7707492576bdbfa8c1dbe7d90791df31e4773	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a5d00dff97118a32fcf5fec7a4c3f864c4620c4e	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bf841d43f7a33d75675ba7f4e214ac1c67913065	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ce8ded2e61f47747e31eeefb44dc24a2160a7e32	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_xen.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a5d00dff97118a32fcf5fec7a4c3f864c4620c4e",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "59e7707492576bdbfa8c1dbe7d90791df31e4773",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "bf841d43f7a33d75675ba7f4e214ac1c67913065",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "ce8ded2e61f47747e31eeefb44dc24a2160a7e32",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "be03c4fe72384366fd4077a70966bd3b8fc49013",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1ab4de11232e83b875b071aa44d1155634ca8a1e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7cc9dbae8a5f73bd555130384ea256018d28f283",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3e0359f151ac151abe3fa71040e450ed69cb824b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8d3fc907d060c4fb33203e616a395a22083b6566",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4f0e9244770f5b75a16d8c0929063cd336926764",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5f6a8974e9ef317fe63f88bab1f33070195dd147",
              "versionType": "git"
            },
            {
              "lessThan": "4.15",
              "status": "affected",
              "version": "4.14.308",
              "versionType": "semver"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.276",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.235",
              "versionType": "semver"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.173",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.100",
              "versionType": "semver"
            },
            {
              "lessThan": "6.2",
              "status": "affected",
              "version": "6.1.18",
              "versionType": "semver"
            },
            {
              "lessThan": "6.3",
              "status": "affected",
              "version": "6.2.5",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_xen.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "9E08C858-E25B-40F9-B5B6-344EFFDB2285",
              "versionEndExcluding": "6.12.75",
              "versionStartIncluding": "4.14.308",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "B4B8CDA9-BADF-4CF5-8B3B-702DE8EEA40B",
              "versionEndExcluding": "6.18.16",
              "versionStartIncluding": "6.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "373EEEDA-FAA1-4FB4-B6ED-DB4DD99DBE67",
              "versionEndExcluding": "6.19.6",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/xen: protect xen_9pfs_front_free against concurrent calls\n\nThe xenwatch thread can race with other back-end change notifications\nand call xen_9pfs_front_free() twice, hitting the observed general\nprotection fault due to a double-free. Guard the teardown path so only\none caller can release the front-end state at a time, preventing the\ncrash.\n\nThis is a fix for the following double-free:\n\n[   27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI\n[   27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none)\n[   27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150\n[   27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 \u003c48\u003e 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42\n[   27.052377] RSP: e02b:ffffc9004016fdd0 EFLAGS: 00010246\n[   27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX: 0000000000000000\n[   27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000\n[   27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000\n[   27.052393] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68\n[   27.052397] R13: 0000000000000200 R14: 0000000000000000 R15: ffff88800a887040\n[   27.052404] FS:  0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000\n[   27.052408] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   27.052412] CR2: 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660\n[   27.052418] Call Trace:\n[   27.052420]  \u003cTASK\u003e\n[   27.052422]  xen_9pfs_front_changed+0x5d5/0x720\n[   27.052426]  ? xenbus_otherend_changed+0x72/0x140\n[   27.052430]  ? __pfx_xenwatch_thread+0x10/0x10\n[   27.052434]  xenwatch_thread+0x94/0x1c0\n[   27.052438]  ? __pfx_autoremove_wake_function+0x10/0x10\n[   27.052442]  kthread+0xf8/0x240\n[   27.052445]  ? __pfx_kthread+0x10/0x10\n[   27.052449]  ? __pfx_kthread+0x10/0x10\n[   27.052452]  ret_from_fork+0x16b/0x1a0\n[   27.052456]  ? __pfx_kthread+0x10/0x10\n[   27.052459]  ret_from_fork_asm+0x1a/0x30\n[   27.052463]  \u003c/TASK\u003e\n[   27.052465] Modules linked in:\n[   27.052471] ---[ end trace 0000000000000000 ]---"
    }
  ],
  "id": "CVE-2026-43249",
  "lastModified": "2026-06-17T10:49:14.203",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-06T12:16:45.493",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/59e7707492576bdbfa8c1dbe7d90791df31e4773"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a5d00dff97118a32fcf5fec7a4c3f864c4620c4e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/bf841d43f7a33d75675ba7f4e214ac1c67913065"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ce8ded2e61f47747e31eeefb44dc24a2160a7e32"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-415"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-43249 (GCVE-0-2026-43249)

Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-08-05 12:26

Title

9p/xen: protect xen_9pfs_front_free against concurrent calls

Summary

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/a5d00dff97118a32f…
https://git.kernel.org/stable/c/59e7707492576bdbf…
https://git.kernel.org/stable/c/bf841d43f7a33d756…
https://git.kernel.org/stable/c/ce8ded2e61f47747e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c15fe55d14b3b4ded5af2a3260877460a6ffb8ad , < a5d00dff97118a32fcf5fec7a4c3f864c4620c4e (git) Affected: c15fe55d14b3b4ded5af2a3260877460a6ffb8ad , < 59e7707492576bdbfa8c1dbe7d90791df31e4773 (git) Affected: c15fe55d14b3b4ded5af2a3260877460a6ffb8ad , < bf841d43f7a33d75675ba7f4e214ac1c67913065 (git) Affected: c15fe55d14b3b4ded5af2a3260877460a6ffb8ad , < ce8ded2e61f47747e31eeefb44dc24a2160a7e32 (git) Affected: be03c4fe72384366fd4077a70966bd3b8fc49013 (git) Affected: 1ab4de11232e83b875b071aa44d1155634ca8a1e (git) Affected: 7cc9dbae8a5f73bd555130384ea256018d28f283 (git) Affected: 3e0359f151ac151abe3fa71040e450ed69cb824b (git) Affected: 8d3fc907d060c4fb33203e616a395a22083b6566 (git) Affected: 4f0e9244770f5b75a16d8c0929063cd336926764 (git) Affected: 5f6a8974e9ef317fe63f88bab1f33070195dd147 (git) Affected: 4.14.308 , < 4.15 (semver) Affected: 4.19.276 , < 4.20 (semver) Affected: 5.4.235 , < 5.5 (semver) Affected: 5.10.173 , < 5.11 (semver) Affected: 5.15.100 , < 5.16 (semver) Affected: 6.1.18 , < 6.2 (semver) Affected: 6.2.5 , < 6.3 (semver)
Linux	Linux	Affected: 6.3 Unaffected: 0 , < 6.3 (semver) Unaffected: 6.12.75 , ≤ 6.12.* (semver) Unaffected: 6.18.16 , ≤ 6.18.* (semver) Unaffected: 6.19.6 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_xen.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a5d00dff97118a32fcf5fec7a4c3f864c4620c4e",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "59e7707492576bdbfa8c1dbe7d90791df31e4773",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "bf841d43f7a33d75675ba7f4e214ac1c67913065",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "lessThan": "ce8ded2e61f47747e31eeefb44dc24a2160a7e32",
              "status": "affected",
              "version": "c15fe55d14b3b4ded5af2a3260877460a6ffb8ad",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "be03c4fe72384366fd4077a70966bd3b8fc49013",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1ab4de11232e83b875b071aa44d1155634ca8a1e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7cc9dbae8a5f73bd555130384ea256018d28f283",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3e0359f151ac151abe3fa71040e450ed69cb824b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8d3fc907d060c4fb33203e616a395a22083b6566",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4f0e9244770f5b75a16d8c0929063cd336926764",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5f6a8974e9ef317fe63f88bab1f33070195dd147",
              "versionType": "git"
            },
            {
              "lessThan": "4.15",
              "status": "affected",
              "version": "4.14.308",
              "versionType": "semver"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.276",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.235",
              "versionType": "semver"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.173",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.100",
              "versionType": "semver"
            },
            {
              "lessThan": "6.2",
              "status": "affected",
              "version": "6.1.18",
              "versionType": "semver"
            },
            {
              "lessThan": "6.3",
              "status": "affected",
              "version": "6.2.5",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_xen.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.16",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.6",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.14.308",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.276",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.4.235",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.10.173",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.15.100",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.1.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.2.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/xen: protect xen_9pfs_front_free against concurrent calls\n\nThe xenwatch thread can race with other back-end change notifications\nand call xen_9pfs_front_free() twice, hitting the observed general\nprotection fault due to a double-free. Guard the teardown path so only\none caller can release the front-end state at a time, preventing the\ncrash.\n\nThis is a fix for the following double-free:\n\n[   27.052347] Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI\n[   27.052357] CPU: 0 UID: 0 PID: 32 Comm: xenwatch Not tainted 6.18.0-02087-g51ab33fc0a8b-dirty #60 PREEMPT(none)\n[   27.052363] RIP: e030:xen_9pfs_front_free+0x1d/0x150\n[   27.052368] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 55 41 54 55 48 89 fd 48 c7 c7 48 d0 92 85 53 e8 cb cb 05 00 48 8b 45 08 48 8b 55 00 \u003c48\u003e 3b 28 0f 85 f9 28 35 fe 48 3b 6a 08 0f 85 ef 28 35 fe 48 89 42\n[   27.052377] RSP: e02b:ffffc9004016fdd0 EFLAGS: 00010246\n[   27.052381] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88800d66e400 RCX: 0000000000000000\n[   27.052385] RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000000 RDI: 0000000000000000\n[   27.052389] RBP: ffff88800a887040 R08: 0000000000000000 R09: 0000000000000000\n[   27.052393] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888009e46b68\n[   27.052397] R13: 0000000000000200 R14: 0000000000000000 R15: ffff88800a887040\n[   27.052404] FS:  0000000000000000(0000) GS:ffff88808ca57000(0000) knlGS:0000000000000000\n[   27.052408] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   27.052412] CR2: 00007f9714004360 CR3: 0000000004834000 CR4: 0000000000050660\n[   27.052418] Call Trace:\n[   27.052420]  \u003cTASK\u003e\n[   27.052422]  xen_9pfs_front_changed+0x5d5/0x720\n[   27.052426]  ? xenbus_otherend_changed+0x72/0x140\n[   27.052430]  ? __pfx_xenwatch_thread+0x10/0x10\n[   27.052434]  xenwatch_thread+0x94/0x1c0\n[   27.052438]  ? __pfx_autoremove_wake_function+0x10/0x10\n[   27.052442]  kthread+0xf8/0x240\n[   27.052445]  ? __pfx_kthread+0x10/0x10\n[   27.052449]  ? __pfx_kthread+0x10/0x10\n[   27.052452]  ret_from_fork+0x16b/0x1a0\n[   27.052456]  ? __pfx_kthread+0x10/0x10\n[   27.052459]  ret_from_fork_asm+0x1a/0x30\n[   27.052463]  \u003c/TASK\u003e\n[   27.052465] Modules linked in:\n[   27.052471] ---[ end trace 0000000000000000 ]---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - The vulnerable 9p Xen frontend is reached through Xenbus/backend state changes from a paired Xen backend or service domain on the same host/logical I/O fabric. It is not directly routable over IP, but it is reachable across an adjacent inter-domain channel.\nAC:L - A malicious backend can repeatedly queue the state transitions/removal paths that lead to concurrent or repeated xen_9pfs_front_free() calls. The trigger does not depend on conditions outside the attacker-controlled backend notification sequence.\nPR:N - No privileges in the vulnerable guest are required; the guest frontend accepts the triggering state changes from its configured backend via Xenstore. Control of the backend is the attack position rather than a credential inside the target Linux kernel.\nUI:N - No victim user action is needed after the Xen 9pfs frontend device is present and bound. Backend state changes are processed asynchronously by xenwatch.\nS:U - The corrupted objects and resulting crash/code-execution risk are within the same guest Linux kernel running the vulnerable frontend. The issue does not demonstrate a guest-to-host or hypervisor escape.\nC:H - This is kernel heap memory corruption via double-free of frontend state and associated ring resources. Such corruption can plausibly be shaped into use-after-free/freelist manipulation and arbitrary kernel memory disclosure, so the higher impact is warranted.\nI:H - The double-free can corrupt kernel allocator metadata or free a reallocated object, giving a plausible path to arbitrary write or control-flow compromise. Under the required uncertainty rule, this is scored as high integrity impact.\nA:H - The reported failure is a general protection fault in xenwatch from dereferencing poisoned freed memory. A malicious backend can crash the guest kernel, causing high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:26:52.660Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a5d00dff97118a32fcf5fec7a4c3f864c4620c4e"
        },
        {
          "url": "https://git.kernel.org/stable/c/59e7707492576bdbfa8c1dbe7d90791df31e4773"
        },
        {
          "url": "https://git.kernel.org/stable/c/bf841d43f7a33d75675ba7f4e214ac1c67913065"
        },
        {
          "url": "https://git.kernel.org/stable/c/ce8ded2e61f47747e31eeefb44dc24a2160a7e32"
        }
      ],
      "title": "9p/xen: protect xen_9pfs_front_free against concurrent calls",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43249",
    "datePublished": "2026-05-06T11:28:40.290Z",
    "dateReserved": "2026-05-01T14:12:55.996Z",
    "dateUpdated": "2026-08-05T12:26:52.660Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-43249

CVE-2026-43249 (GCVE-0-2026-43249)

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