CVE-2026-72072 (GCVE-0-2026-72072)
Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:40
VLAI
EPSS
VEX
Title
net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete
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).
Severity
7.8 (High)
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb
(git)
Affected: b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < 218cc15a4c907659ad4b0e68c535c61594311205 (git) Affected: b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < 4a5073b7b30243658f58b2d2d35a823da7fd34d9 (git) Affected: b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < ed3cc4218070d6b98bf5fb456dccae424fd38c4f (git) Affected: b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < 088873af13590ebde10de2ade847f57a05ec61c6 (git) Affected: b7c9400cbc48c3713190b3bce4e0c87e924e4104 , < de74d8fd10291763d97b218f09adcc7513c975e4 (git) |
guessed | |
| Linux | Linux |
Affected:
6.1
Unaffected: 0 , < 6.1 (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c"
],
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
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"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": [
{
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"versionStartIncluding": "6.1",
"vulnerable": true
},
{
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},
{
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"versionEndExcluding": "6.12.97",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
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"vulnerable": true
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{
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}
],
"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": [
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"url": "https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb"
},
{
"url": "https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205"
},
{
"url": "https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9"
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{
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{
"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"
}
}
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"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",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-72072",
"date": "2026-10-01",
"epss": "0.00171",
"percentile": "0.05841"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"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",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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},
{
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"status": "unaffected",
"version": "6.12.97",
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{
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}
],
"cveTags": [],
"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)."
}
],
"id": "CVE-2026-72072",
"lastModified": "2026-08-17T06:18:05.787",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T06:21:16.943",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/088873af13590ebde10de2ade847f57a05ec61c6"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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},
{
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"url": "https://git.kernel.org/stable/c/ed3cc4218070d6b98bf5fb456dccae424fd38c4f"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-09-24T03:39:34+00:00",
"cve": "CVE-2026-72072",
"id": "CVE-2026-72072",
"initial_release_date": "2026-08-15T00:00:00+00:00",
"product_status:fixed": "303",
"product_status:known_affected": "112",
"product_status:known_not_affected": "76",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72072.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "important",
"current_release_date": "2026-09-28T23:49:49Z",
"cve": "CVE-2026-72072",
"id": "CVE-2026-72072",
"initial_release_date": "2026-08-28T01:01:27Z",
"product_status:first_fixed": "133",
"product_status:known_affected": "421",
"product_status:known_not_affected": "254",
"product_status:recommended": "258",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-72072",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72072.json",
"version": "12"
}
}
}
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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