CVE-2026-72072 (GCVE-0-2026-72072)
Vulnerability from cvelistv5
Published
2026-08-15 05:52
Modified
2026-08-17 05:40
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete
When an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed
the per-SC metadata_dst with metadata_dst_free(), which kfree()s the
object unconditionally and ignores the dst reference count. The RX
datapath in mlx5e_macsec_offload_handle_rx_skb() looks up the SC under
rcu_read_lock() via xa_load(), takes a reference with dst_hold() and
attaches the dst to the skb with skb_dst_set(). A reader that already
obtained the rx_sc pointer can race with the delete path and operate on
freed memory.
Fix the owner side by dropping the reference with dst_release() instead
of freeing unconditionally, and convert the RX datapath to
dst_hold_safe() so a reader racing the SC delete cannot attach a dst
whose last reference was just dropped; only attach it when a reference
was actually taken.
mlx5e_macsec_add_rxsc() also published sc_xarray_element via xa_alloc()
before rx_sc->md_dst was allocated and initialised, so a datapath reader
that looked the SC up by fs_id could observe rx_sc with md_dst still
NULL or, on weakly-ordered architectures, a non-NULL md_dst pointer
whose contents were not yet visible. NULL-check the xa_load() result and
md_dst on the datapath, and reorder add_rxsc() so the xa_alloc() publish
happens only after md_dst is fully initialised; the xarray RCU publish
then pairs with the rcu_read_lock()/xa_load() in the datapath.
Note: macsec_del_rxsc_ctx() also kfree()s rx_sc->sc_xarray_element
without an RCU grace period while the same datapath reads it under
rcu_read_lock(); that is a separate pre-existing issue left to a
follow-up patch.
Found by 0sec automated security-research tooling (https://0sec.ai).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 Version: b7c9400cbc48c3713190b3bce4e0c87e924e4104 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
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{
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},
{
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"status": "affected",
"version": "b7c9400cbc48c3713190b3bce4e0c87e924e4104",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
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}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.1"
},
{
"lessThan": "6.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"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": "6.1.178",
"versionStartIncluding": "6.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
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{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete\n\nWhen an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed\nthe per-SC metadata_dst with metadata_dst_free(), which kfree()s the\nobject unconditionally and ignores the dst reference count. The RX\ndatapath in mlx5e_macsec_offload_handle_rx_skb() looks up the SC under\nrcu_read_lock() via xa_load(), takes a reference with dst_hold() and\nattaches the dst to the skb with skb_dst_set(). A reader that already\nobtained the rx_sc pointer can race with the delete path and operate on\nfreed memory.\n\nFix the owner side by dropping the reference with dst_release() instead\nof freeing unconditionally, and convert the RX datapath to\ndst_hold_safe() so a reader racing the SC delete cannot attach a dst\nwhose last reference was just dropped; only attach it when a reference\nwas actually taken.\n\nmlx5e_macsec_add_rxsc() also published sc_xarray_element via xa_alloc()\nbefore rx_sc-\u003emd_dst was allocated and initialised, so a datapath reader\nthat looked the SC up by fs_id could observe rx_sc with md_dst still\nNULL or, on weakly-ordered architectures, a non-NULL md_dst pointer\nwhose contents were not yet visible. NULL-check the xa_load() result and\nmd_dst on the datapath, and reorder add_rxsc() so the xa_alloc() publish\nhappens only after md_dst is fully initialised; the xarray RCU publish\nthen pairs with the rcu_read_lock()/xa_load() in the datapath.\n\nNote: macsec_del_rxsc_ctx() also kfree()s rx_sc-\u003esc_xarray_element\nwithout an RCU grace period while the same datapath reads it under\nrcu_read_lock(); that is a separate pre-existing issue left to a\nfollow-up patch.\n\nFound by 0sec automated security-research tooling (https://0sec.ai)."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The UAF is reached by racing MACSEC_CMD_DEL_RXSC/ADD_RXSC netlink configuration (GENL_ADMIN_PERM) against mlx5e MACsec RX processing; the privileged genlink/rtnl control path is required to trigger the bug, not remote packets alone.\nAC:L - An attacker with CAP_NET_ADMIN can drive both sides by looping RX SC add/delete while flooding MACsec-offloaded RX traffic on the mlx5e netdev, reliably winning the RCU race between xa_load/dst_hold and metadata_dst_free.\nPR:L - MACsec offload mutations require GENL_ADMIN_PERM (CAP_NET_ADMIN); on Mellanox ConnectX/BlueField systems this is reachable by cloud tenants with SR-IOV VFs, containers, or user/network namespaces without init-namespace root.\nUI:N - No victim user action is needed; automated concurrent netlink MACsec operations and incoming MACsec-offloaded frames on an active mlx5e interface suffice once MACsec offload is configured.\nS:U - Impact is kernel heap use-after-free and memory corruption within the host kernel on the mlx5 NIC; it enables local privilege escalation but does not by itself cross VM, IOMMU, or hypervisor security boundaries.\nC:H - The race calls dst_hold() and skb_dst_set() on a freed metadata_dst, a classic slab UAF that can disclose kernel memory through subsequent dst_entry and MACsec skb metadata handling.\nI:H - Freed metadata_dst objects can be reallocated via heap spraying while the RX datapath still references them, enabling refcount corruption and arbitrary kernel memory writes or control-flow hijack beyond a mere crash.\nA:H - Concurrent use of freed md_dst during mlx5e MACsec RX processing can cause immediate kernel oops, BUG, or panic on datacenter/cloud hosts using mlx5 hardware MACsec offload, fully denying system availability."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:40:03.099Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb"
},
{
"url": "https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205"
},
{
"url": "https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9"
},
{
"url": "https://git.kernel.org/stable/c/ed3cc4218070d6b98bf5fb456dccae424fd38c4f"
},
{
"url": "https://git.kernel.org/stable/c/088873af13590ebde10de2ade847f57a05ec61c6"
},
{
"url": "https://git.kernel.org/stable/c/de74d8fd10291763d97b218f09adcc7513c975e4"
}
],
"title": "net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72072",
"datePublished": "2026-08-15T05:52:23.946Z",
"dateReserved": "2026-08-09T03:40:39.904Z",
"dateUpdated": "2026-08-17T05:40:03.099Z",
"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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