CVE-2026-64522 (GCVE-0-2026-64522)
Vulnerability from cvelistv5 – Published: 2026-07-25 09:14 – Updated: 2026-08-05 12:42
VLAI
EPSS
VEX
Title
net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA
mlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating
software state and skipping hardware offload setup.
That path jumps to the common success label before taking the eswitch mode
block. After tunnel-mode validation was moved earlier, the common success
label unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs,
this decrements esw->offloads.num_block_mode without a matching increment.
Return directly after installing the acquire SA offload handle, so only the
paths that successfully called mlx5_eswitch_block_mode() call the matching
unblock.
Severity
8.8 (High)
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < b5bd4249e430f5963d559708ee96a671716d2400
(git)
Affected: 22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < ecafd8284e527666e83261e6e57a7c7341d591cb (git) Affected: 22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < abe003b33223ff33552f291644bf35d9c2f992fb (git) Affected: 993c4ba71596c30418ba5a0ddcf4f9c2f431466a (git) Affected: 6.17.4 , < 6.18 (semver) |
|
| Linux | Linux |
Affected:
6.18
Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.34 , ≤ 6.18.* (semver) Unaffected: 7.0.11 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix) |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.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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"status": "affected",
"version": "22239eb258bc1e6ccdb2d3502fce1cc2b2a88386",
"versionType": "git"
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{
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"status": "affected",
"version": "22239eb258bc1e6ccdb2d3502fce1cc2b2a88386",
"versionType": "git"
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{
"status": "affected",
"version": "993c4ba71596c30418ba5a0ddcf4f9c2f431466a",
"versionType": "git"
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{
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"status": "affected",
"version": "6.17.4",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
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{
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"status": "unaffected",
"version": "0",
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"status": "unaffected",
"version": "6.18.34",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.0.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
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],
"cpeApplicability": [
{
"nodes": [
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1",
"versionStartIncluding": "6.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.17.4",
"vulnerable": true
}
],
"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: Fix eswitch mode block underflow on IPsec acquire SA\n\nmlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating\nsoftware state and skipping hardware offload setup.\n\nThat path jumps to the common success label before taking the eswitch mode\nblock. After tunnel-mode validation was moved earlier, the common success\nlabel unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs,\nthis decrements esw-\u003eoffloads.num_block_mode without a matching increment.\n\nReturn directly after installing the acquire SA offload handle, so only the\npaths that successfully called mlx5_eswitch_block_mode() call the matching\nunblock."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - A remote TCP SYN can cause the kernel to route a SYN-ACK through an administrator-configured outbound mlx5 IPsec policy, reaching xfrm_state_find() and the vulnerable acquire-SA callback.\nAC:L - Once the affected packet-offload policy is deployed without a matching SA, the first matching flow deterministically performs the unmatched decrement; no race must be won.\nPR:N - The remote peer needs no credentials or capabilities; configuring the mlx5 IPsec policy is a deployment prerequisite, not an attacker privilege.\nUI:R - The highest-impact stale-object path requires an administrator to request an eswitch mode transition after the attacker has cancelled the live mode-block reference.\nS:U - The resulting corruption affects the same host kernel and mlx5 device security authority, without crossing a VM, IOMMU, or sandbox boundary.\nC:H - The incorrectly permitted mode transition frees mlx5 IPsec structures while XFRM policies retain references to them, creating subsequent use-after-free callbacks capable of exposing kernel memory.\nI:H - The stale policy and flow-table references can be reclaimed and attacker-influenced, making the resulting kernel use-after-free potentially exploitable for arbitrary writes or control-flow hijacking.\nA:H - Mode-transition teardown or later automatic policy expiration can dereference freed IPsec and flow-rule objects, causing a kernel warning, oops, or panic."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:42:35.590Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/b5bd4249e430f5963d559708ee96a671716d2400"
},
{
"url": "https://git.kernel.org/stable/c/ecafd8284e527666e83261e6e57a7c7341d591cb"
},
{
"url": "https://git.kernel.org/stable/c/abe003b33223ff33552f291644bf35d9c2f992fb"
}
],
"title": "net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64522",
"datePublished": "2026-07-25T09:14:47.404Z",
"dateReserved": "2026-07-19T15:36:31.794Z",
"dateUpdated": "2026-08-05T12:42:35.590Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-64522",
"date": "2026-10-12",
"epss": "0.00512",
"percentile": "0.41937"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
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"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "22239eb258bc1e6ccdb2d3502fce1cc2b2a88386",
"versionType": "git"
},
{
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"version": "22239eb258bc1e6ccdb2d3502fce1cc2b2a88386",
"versionType": "git"
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"version": "993c4ba71596c30418ba5a0ddcf4f9c2f431466a",
"versionType": "git"
},
{
"lessThan": "6.18",
"status": "affected",
"version": "6.17.4",
"versionType": "semver"
}
]
},
{
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"product": "Linux",
"programFiles": [
"drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"version": "6.18"
},
{
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"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.18.34",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA\n\nmlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating\nsoftware state and skipping hardware offload setup.\n\nThat path jumps to the common success label before taking the eswitch mode\nblock. After tunnel-mode validation was moved earlier, the common success\nlabel unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs,\nthis decrements esw-\u003eoffloads.num_block_mode without a matching increment.\n\nReturn directly after installing the acquire SA offload handle, so only the\npaths that successfully called mlx5_eswitch_block_mode() call the matching\nunblock."
}
],
"id": "CVE-2026-64522",
"lastModified": "2026-07-27T05:16:56.213",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-25T10:17:38.497",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/abe003b33223ff33552f291644bf35d9c2f992fb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b5bd4249e430f5963d559708ee96a671716d2400"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ecafd8284e527666e83261e6e57a7c7341d591cb"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-07-29T13:28:19+00:00",
"cve": "CVE-2026-64522",
"id": "CVE-2026-64522",
"initial_release_date": "2026-07-25T00:00:00+00:00",
"product_status:known_affected": "198",
"product_status:known_not_affected": "76",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64522.json",
"version": "3"
}
}
}
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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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