FKIE_CVE-2026-43249
Vulnerability from fkie_nvd - Published: 2026-05-06 12:16 - Updated: 2026-05-11 13:10
Severity ?
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
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
{
"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": "2026-05-11T13:10:20.973",
"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"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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