FKIE_CVE-2026-74615
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
vxlan: do not arm the ageing timer on a device that is down
vxlan_changelink() arms vxlan->age_timer whenever the requested ageing
interval differs from the configured one:
if (conf.age_interval != vxlan->cfg.age_interval)
mod_timer(&vxlan->age_timer, jiffies);
There is no netif_running() test, so the timer is armed even on a device
that was never brought up. The only synchronous cancel in the driver is
the timer_delete_sync() in vxlan_stop(), which is .ndo_stop.
netif_close_many() drops devices without IFF_UP before
__dev_close_many() runs, so that cancel is skipped for such a device.
vxlan_setup() sets dev->needs_free_netdev = true and age_timer is a
member of struct vxlan_dev, so free_netdev() releases the allocation the
timer lives in while it is still queued on a timer_base.
expire_timers() unlinks the entry before it loads timer->function, so
the timer core writes through the freed object's list pointers:
BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654
Write of size 8 at addr ffff00001adace68 by task true/192
__asan_store8+0x84/0xac
__run_timers+0x208/0x654
run_timer_softirq+0x154/0x18c
Allocated by task 189:
alloc_netdev_mqs+0x64/0x720
rtnl_create_link+0x4ac/0x520
rtnl_newlink+0x758/0xd00
Freed by task 191:
netdev_release+0x40/0x58
netdev_run_todo+0x4a4/0x8c0
rtnl_dellink+0x200/0x4e8
The rtnl operations involved are netns-scoped, so an unprivileged user
can perform them in a new user and network namespace.
Arming the timer on a down device never had an effect: vxlan_cleanup()
returns early on !netif_running(), and vxlan_open() arms the timer for
any non-zero interval once the device is brought up. Add the missing
test.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "be44d79d14d7f9ae7c8ffb7272142005341b5123",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "26c179d47403d2f919ee914cc02c31d896b59fee",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "9dc561f0522c35bdd66e0646a748814a138ec4ca",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "619dd29045e439d0b0f8c6d4fec1af447a050680",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "6b095e99b9e67ea31f0c4b00260e010898253519",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "46bb297ad77680e009244f067f27d51cf5b8c7cf",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "6b4119af544996a545cf84b16f1dbce829ba0de8",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
},
{
"lessThan": "b37971686ec59fb027fa4910ba16805e68fddb97",
"status": "affected",
"version": "40051c4dcad5b374156ad9cceae8d15c0ef1cb95",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.0"
},
{
"lessThan": "5.0",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: do not arm the ageing timer on a device that is down\n\nvxlan_changelink() arms vxlan-\u003eage_timer whenever the requested ageing\ninterval differs from the configured one:\n\n\tif (conf.age_interval != vxlan-\u003ecfg.age_interval)\n\t\tmod_timer(\u0026vxlan-\u003eage_timer, jiffies);\n\nThere is no netif_running() test, so the timer is armed even on a device\nthat was never brought up. The only synchronous cancel in the driver is\nthe timer_delete_sync() in vxlan_stop(), which is .ndo_stop.\nnetif_close_many() drops devices without IFF_UP before\n__dev_close_many() runs, so that cancel is skipped for such a device.\n\nvxlan_setup() sets dev-\u003eneeds_free_netdev = true and age_timer is a\nmember of struct vxlan_dev, so free_netdev() releases the allocation the\ntimer lives in while it is still queued on a timer_base.\nexpire_timers() unlinks the entry before it loads timer-\u003efunction, so\nthe timer core writes through the freed object\u0027s list pointers:\n\n BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654\n Write of size 8 at addr ffff00001adace68 by task true/192\n __asan_store8+0x84/0xac\n __run_timers+0x208/0x654\n run_timer_softirq+0x154/0x18c\n Allocated by task 189:\n alloc_netdev_mqs+0x64/0x720\n rtnl_create_link+0x4ac/0x520\n rtnl_newlink+0x758/0xd00\n Freed by task 191:\n netdev_release+0x40/0x58\n netdev_run_todo+0x4a4/0x8c0\n rtnl_dellink+0x200/0x4e8\n\nThe rtnl operations involved are netns-scoped, so an unprivileged user\ncan perform them in a new user and network namespace.\n\nArming the timer on a down device never had an effect: vxlan_cleanup()\nreturns early on !netif_running(), and vxlan_open() arms the timer for\nany non-zero interval once the device is brought up. Add the missing\ntest.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
}
],
"id": "CVE-2026-74615",
"lastModified": "2026-08-25T06:18:39.610",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.0,
"impactScore": 6.0,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-22T16:16:34.143",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/26c179d47403d2f919ee914cc02c31d896b59fee"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/46bb297ad77680e009244f067f27d51cf5b8c7cf"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/619dd29045e439d0b0f8c6d4fec1af447a050680"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6b095e99b9e67ea31f0c4b00260e010898253519"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6b4119af544996a545cf84b16f1dbce829ba0de8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9dc561f0522c35bdd66e0646a748814a138ec4ca"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b37971686ec59fb027fa4910ba16805e68fddb97"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/be44d79d14d7f9ae7c8ffb7272142005341b5123"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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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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.
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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