CVE-2026-68432 (GCVE-0-2026-68432)
Vulnerability from cvelistv5
Published
2026-08-12 00:07
Modified
2026-08-19 16:35
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
vxlan: require CAP_NET_ADMIN in the device netns for changelink
A tunnel changelink() operates on at most two netns, dev_net(dev) and
the sticky underlay netns vxlan->net. They differ once the device is
created in or moved to a netns other than the one the request runs in.
The rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev),
so a caller privileged there but not in vxlan->net can rewrite a vxlan
device whose underlay lives in vxlan->net.
vxlan_changelink() validates and applies the new configuration against
vxlan->net (vxlan_config_validate(vxlan->net, ...)) and can reopen the
underlay socket in that netns, so the same reasoning as the tunnel
changelink series applies here.
Gate vxlan_changelink() with rtnl_dev_link_net_capable(), at the top of
the op before any attribute is parsed, matching ipgre_changelink() and
the rest of the "require CAP_NET_ADMIN in the device netns for
changelink" series.
Found by 0sec automated security-research tooling (https://0sec.ai).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 Version: 8bcdc4f3a20be949df54b67e5ae2734daabb5792 |
||
{
"containers": {
"cna": {
"affected": [
{
"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": "b95a8743e58f7efed5ddc4cb73829b66f17feab0",
"status": "affected",
"version": "8bcdc4f3a20be949df54b67e5ae2734daabb5792",
"versionType": "git"
},
{
"lessThan": "7465ade989ba84adc2bfa58bad3ca25d249f0f7a",
"status": "affected",
"version": "8bcdc4f3a20be949df54b67e5ae2734daabb5792",
"versionType": "git"
},
{
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"status": "affected",
"version": "8bcdc4f3a20be949df54b67e5ae2734daabb5792",
"versionType": "git"
},
{
"lessThan": "b3793d7dccb192ffff29894d11824db6251acdd5",
"status": "affected",
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"versionType": "git"
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{
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"versionType": "git"
},
{
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"status": "affected",
"version": "8bcdc4f3a20be949df54b67e5ae2734daabb5792",
"versionType": "git"
},
{
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"status": "affected",
"version": "8bcdc4f3a20be949df54b67e5ae2734daabb5792",
"versionType": "git"
},
{
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"status": "affected",
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"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": "4.11"
},
{
"lessThan": "4.11",
"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": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.265",
"versionStartIncluding": "4.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "4.11",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.42",
"versionStartIncluding": "4.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "4.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "4.11",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: require CAP_NET_ADMIN in the device netns for changelink\n\nA tunnel changelink() operates on at most two netns, dev_net(dev) and\nthe sticky underlay netns vxlan-\u003enet. They differ once the device is\ncreated in or moved to a netns other than the one the request runs in.\nThe rtnl changelink path checks CAP_NET_ADMIN only against dev_net(dev),\nso a caller privileged there but not in vxlan-\u003enet can rewrite a vxlan\ndevice whose underlay lives in vxlan-\u003enet.\n\nvxlan_changelink() validates and applies the new configuration against\nvxlan-\u003enet (vxlan_config_validate(vxlan-\u003enet, ...)) and can reopen the\nunderlay socket in that netns, so the same reasoning as the tunnel\nchangelink series applies here.\n\nGate vxlan_changelink() with rtnl_dev_link_net_capable(), at the top of\nthe op before any attribute is parsed, matching ipgre_changelink() and\nthe rest of the \"require CAP_NET_ADMIN in the device netns for\nchangelink\" series.\n\nFound by 0sec automated security-research tooling (https://0sec.ai)."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Exploitation requires issuing an RTM_NEWLINK changelink request over an rtnetlink socket on the local system, matching the kernel guidance that netlink configuration paths are Local.\nAC:L - Once a cross-namespace vxlan device is present in the caller\u0027s netns, the missing check is bypassed by a single deterministic netlink changelink call with no race, timing, or memory-layout dependency.\nPR:L - The rtnl entry path only requires CAP_NET_ADMIN in dev_net(dev), which an unprivileged user obtains inside a user namespace via unshare --user --map-root-user --net; no privilege in the underlay netns vxlan-\u003enet is needed.\nUI:N - The attack is fully programmatic through netlink from the attacker\u0027s own process; no victim action such as mounting, opening a file, or clicking is required.\nS:C - Authorization is evaluated against dev_net(dev) while the configuration is validated and applied against vxlan-\u003enet, so the impact crosses from the attacker\u0027s net/user namespace into another tenant\u0027s or the host\u0027s network namespace.\nC:H - The attacker can rewrite IFLA_VXLAN_GROUP/LOCAL and the underlay IFLA_VXLAN_LINK so encapsulated overlay traffic in the victim netns is sent to an attacker-controlled endpoint, exposing tunneled payloads.\nI:H - Unauthorized changelink mutates live tunnel state in the victim underlay netns (remote/local addresses, lower device, TOS/TTL/label, learning and proxy/RSC flags, default-remote FDB entries), enabling redirection and injection of overlay traffic.\nA:H - Rewriting the remote group, source address, or lower device tears down and re-establishes multicast group membership and forwarding state, causing sustained loss of connectivity for every service riding the affected VXLAN overlay."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:35:30.743Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/b95a8743e58f7efed5ddc4cb73829b66f17feab0"
},
{
"url": "https://git.kernel.org/stable/c/7465ade989ba84adc2bfa58bad3ca25d249f0f7a"
},
{
"url": "https://git.kernel.org/stable/c/0aa580a8bbbed2507b4582a1f0ef581d480d06ed"
},
{
"url": "https://git.kernel.org/stable/c/b3793d7dccb192ffff29894d11824db6251acdd5"
},
{
"url": "https://git.kernel.org/stable/c/32d10c46bfde3e9b274e9e1bd6399d0ebea8f60f"
},
{
"url": "https://git.kernel.org/stable/c/730c7e5fea7f06e0cdf21c547222ec93234fd1d6"
},
{
"url": "https://git.kernel.org/stable/c/e8ad0d311e225939a9a6c745d6cc384c7364ec87"
},
{
"url": "https://git.kernel.org/stable/c/3a61bd9637f3d929aa846e4eb3d98b48c26fcb0e"
}
],
"title": "vxlan: require CAP_NET_ADMIN in the device netns for changelink",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68432",
"datePublished": "2026-08-12T00:07:18.806Z",
"dateReserved": "2026-07-30T09:28:09.393Z",
"dateUpdated": "2026-08-19T16:35:30.743Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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