CVE-2026-23440 (GCVE-0-2026-23440)
Vulnerability from cvelistv5
Published
2026-04-03 15:15
Modified
2026-04-27 14:02
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix race condition during IPSec ESN update
In IPSec full offload mode, the device reports an ESN (Extended
Sequence Number) wrap event to the driver. The driver validates this
event by querying the IPSec ASO and checking that the esn_event_arm
field is 0x0, which indicates an event has occurred. After handling
the event, the driver must re-arm the context by setting esn_event_arm
back to 0x1.
A race condition exists in this handling path. After validating the
event, the driver calls mlx5_accel_esp_modify_xfrm() to update the
kernel's xfrm state. This function temporarily releases and
re-acquires the xfrm state lock.
So, need to acknowledge the event first by setting esn_event_arm to
0x1. This prevents the driver from reprocessing the same ESN update if
the hardware sends events for other reason. Since the next ESN update
only occurs after nearly 2^31 packets are received, there's no risk of
missing an update, as it will happen long after this handling has
finished.
Processing the event twice causes the ESN high-order bits (esn_msb) to
be incremented incorrectly. The driver then programs the hardware with
this invalid ESN state, which leads to anti-replay failures and a
complete halt of IPSec traffic.
Fix this by re-arming the ESN event immediately after it is validated,
before calling mlx5_accel_esp_modify_xfrm(). This ensures that any
spurious, duplicate events are correctly ignored, closing the race
window.
References
Impacted products
{
"containers": {
"cna": {
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"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_offload.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_offload.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": "6.6.130",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.20",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.10",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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: Fix race condition during IPSec ESN update\n\nIn IPSec full offload mode, the device reports an ESN (Extended\nSequence Number) wrap event to the driver. The driver validates this\nevent by querying the IPSec ASO and checking that the esn_event_arm\nfield is 0x0, which indicates an event has occurred. After handling\nthe event, the driver must re-arm the context by setting esn_event_arm\nback to 0x1.\n\nA race condition exists in this handling path. After validating the\nevent, the driver calls mlx5_accel_esp_modify_xfrm() to update the\nkernel\u0027s xfrm state. This function temporarily releases and\nre-acquires the xfrm state lock.\n\nSo, need to acknowledge the event first by setting esn_event_arm to\n0x1. This prevents the driver from reprocessing the same ESN update if\nthe hardware sends events for other reason. Since the next ESN update\nonly occurs after nearly 2^31 packets are received, there\u0027s no risk of\nmissing an update, as it will happen long after this handling has\nfinished.\n\nProcessing the event twice causes the ESN high-order bits (esn_msb) to\nbe incremented incorrectly. The driver then programs the hardware with\nthis invalid ESN state, which leads to anti-replay failures and a\ncomplete halt of IPSec traffic.\n\nFix this by re-arming the ESN event immediately after it is validated,\nbefore calling mlx5_accel_esp_modify_xfrm(). This ensures that any\nspurious, duplicate events are correctly ignored, closing the race\nwindow."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-27T14:02:25.212Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3dffc083292e6872787bd7e34b957627622f9af4"
},
{
"url": "https://git.kernel.org/stable/c/2051c709dce92da3550040aa7949cd5a9c89b14e"
},
{
"url": "https://git.kernel.org/stable/c/96c9c25b74686ac2de15921c9ad30c5ef13af8cd"
},
{
"url": "https://git.kernel.org/stable/c/8d625c15471fb8780125eaef682983a96af77bdc"
},
{
"url": "https://git.kernel.org/stable/c/beb6e2e5976a128b0cccf10d158124422210c5ef"
}
],
"title": "net/mlx5e: Fix race condition during IPSec ESN update",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-23440",
"datePublished": "2026-04-03T15:15:24.596Z",
"dateReserved": "2026-01-13T15:37:46.017Z",
"dateUpdated": "2026-04-27T14:02:25.212Z",
"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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