CVE-2026-99079 (GCVE-0-2026-99079)
Vulnerability from cvelistv5
Published
2026-10-23 12:23
Modified
2026-10-24 14:10
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Prevent stale XSK buffer release on refill retry
When an XDP redirect to an AF_XDP socket fails because its RX ring is
full, the XSK core frees the buffer. During the subsequent batched refill
of a legacy cyclic RQ, mlx5e also releases the WQE's XSK buffer before
allocating a replacement. If that refill succeeds only partially, a WQE
left without a replacement retains its old buffer pointer.
The buffer can meanwhile be allocated to another WQE. A later refill
retry can then free the live buffer through the stale pointer and publish
the same UMEM frame twice.
Mark the WQE as released immediately after the driver-side free. The flag
is already cleared when a replacement buffer is assigned, so refill
retries no longer release stale pointers.
The failure is silent and produces no kernel warning or splat. A
standalone legacy cyclic-RQ zero-copy libxsk reproducer, using 64-byte UDP
traffic offered at 12 Mpps, detected it: stock stopped after 2,854,914
packets in 4.094 seconds, with 4,542 xdp_rx_ring_full events and 64
ownership/double-publication errors. With this change it processed
356,904,225 packets in 30 seconds despite 571,405 xdp_rx_ring_full events,
with no ownership or data errors.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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]
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"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.4"
},
{
"lessThan": "6.4",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.160",
"versionStartIncluding": "6.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.113",
"versionStartIncluding": "6.4",
"vulnerable": true
},
{
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},
{
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"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Prevent stale XSK buffer release on refill retry\n\nWhen an XDP redirect to an AF_XDP socket fails because its RX ring is\nfull, the XSK core frees the buffer. During the subsequent batched refill\nof a legacy cyclic RQ, mlx5e also releases the WQE\u0027s XSK buffer before\nallocating a replacement. If that refill succeeds only partially, a WQE\nleft without a replacement retains its old buffer pointer.\n\nThe buffer can meanwhile be allocated to another WQE. A later refill\nretry can then free the live buffer through the stale pointer and publish\nthe same UMEM frame twice.\n\nMark the WQE as released immediately after the driver-side free. The flag\nis already cleared when a replacement buffer is assigned, so refill\nretries no longer release stale pointers.\n\nThe failure is silent and produces no kernel warning or splat. A\nstandalone legacy cyclic-RQ zero-copy libxsk reproducer, using 64-byte UDP\ntraffic offered at 12 Mpps, detected it: stock stopped after 2,854,914\npackets in 4.094 seconds, with 4,542 xdp_rx_ring_full events and 64\nownership/double-publication errors. With this change it processed\n356,904,225 packets in 30 seconds despite 571,405 xdp_rx_ring_full events,\nwith no ownership or data errors."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - UDP datagrams reaching mlx5 drive mlx5e_completion_event() -\u003e mlx5e_napi_poll() -\u003e mlx5e_poll_rx_cq()/XDP redirect, then mlx5e_napi_xsk_post() -\u003e mlx5e_post_rx_wqes() -\u003e patched mlx5e_xsk_free_rx_wqe(); sustained routable traffic fills the XSK RX ring and triggers stale release.\nAC:L - A sender can sustain small-packet traffic until __xsk_rcv_zc() reports RX-ring-full and mlx5e_xsk_alloc_rx_wqes_batched() refills only part of the missing WQEs; retries are deterministic and require no uncontrolled race or memory layout.\nPR:N - The NIC-CQE/NAPI receive path contains no capability or authentication check; xsk_create()\u0027s CAP_NET_RAW check applies to victim-side AF_XDP provisioning, while the remote UDP sender needs no privileges.\nUI:N - Once the zero-copy XSK pool and XDP redirect are active, xsk_rcv_zc() failure, mlx5e_napi_xsk_post(), and refill retries occur automatically as packets arrive, without further victim action.\nS:U - mlx5e_xsk_free_rx_wqe() corrupts the host kernel\u0027s xsk_buff_pool and mlx5 receive state without crossing a VM, IOMMU, or other security-authority boundary.\nC:H - Duplicate xdp_buff_xsk ownership lets repeated successful __xsk_rcv_zc() calls invoke unbounded xp_release(); in unaligned-UMEM mode, free_heads_cnt can write kernel pointers past the flexible free_heads[] array, yielding heap corruption exploitable for arbitrary disclosure.\nI:H - The duplicate WQEs can make xp_release() write beyond free_heads[], while xp_get_xskb() later trusts pointers popped through the corrupted count; this supplies out-of-bounds and corrupted-pointer write primitives capable of control-flow hijacking.\nA:H - The free_heads[] overflow or a bogus xskb consumed by xp_get_xskb() can oops or panic; additionally, the dma_dev_need_sync refill path can store NULL on allocation failure and have the stale retry pass it to xsk_buff_free()."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-24T14:10:21.247Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/32bbb870078d467479965c21bbc4960c57eea208"
},
{
"url": "https://git.kernel.org/stable/c/34d1db2b18e1c1d189e34dd51923e031815f88e3"
},
{
"url": "https://git.kernel.org/stable/c/639522e5056cade578a324acfa993ec6c9f7f5dc"
},
{
"url": "https://git.kernel.org/stable/c/655f47477054d19de3b138840be229a1a4490d0c"
},
{
"url": "https://git.kernel.org/stable/c/e01620844c5c88b6fcf819d171df8e3976a0e76f"
}
],
"title": "net/mlx5e: Prevent stale XSK buffer release on refill retry",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-99079",
"datePublished": "2026-10-23T12:23:26.458Z",
"dateReserved": "2026-09-25T10:25:14.389Z",
"dateUpdated": "2026-10-24T14:10:21.247Z",
"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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