CVE-2026-64576 (GCVE-0-2026-64576)
Vulnerability from cvelistv5 – Published: 2026-08-05 08:09 – Updated: 2026-08-19 16:28
VLAI
EPSS
VEX
Title
nexthop: initialize extack in nh_res_bucket_migrate()
Summary
In the Linux kernel, the following vulnerability has been resolved:
nexthop: initialize extack in nh_res_bucket_migrate()
nh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to
call_nexthop_res_bucket_notifiers(). When
nh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns
-ENOMEM), the error is propagated back before any notifier sets
extack._msg, and the error path formats the stale pointer with
pr_err_ratelimited("%s\n", extack._msg). With CONFIG_INIT_STACK_NONE
this dereferences uninitialized stack memory:
Oops: general protection fault, probably for non-canonical address ...
KASAN: maybe wild-memory-access in range [...]
RIP: 0010:string (lib/vsprintf.c:730)
vsnprintf (lib/vsprintf.c:2945)
_printk (kernel/printk/printk.c:2504)
nh_res_bucket_migrate (net/ipv4/nexthop.c:1816)
nh_res_table_upkeep (net/ipv4/nexthop.c:1866)
rtm_new_nexthop (net/ipv4/nexthop.c:3323)
rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)
netlink_sendmsg (net/netlink/af_netlink.c:1900)
Kernel panic - not syncing: Fatal exception
Zero-initialize extack so _msg is NULL on error paths that never set it.
Severity
7.1 (High)
Assigner
References
7 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
7c37c7e00411b3d1e0c5292368317aca69d1f324 , < eacd2e2117e8682f937967fda1022e7f1c22d91a
(git)
Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < 37bbd7e1d8df0bec3d187e961783e20c30533d2c (git) Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < c0936c131a71657afc635d0db2ab096d15d473e1 (git) Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < 3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d (git) Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < d536bf205c71f700f6de2086038c3e1d77724715 (git) Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < 18506d7263768d76ac8e057ba55a4d9da50aad66 (git) Affected: 7c37c7e00411b3d1e0c5292368317aca69d1f324 , < 6347c5314cee49f364aaf2e40ff15415a57a116e (git) |
guessed | |
| Linux | Linux |
Affected:
5.13
Unaffected: 0 , < 5.13 (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv4/nexthop.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"version": "5.13"
},
{
"lessThan": "5.13",
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"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"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": "5.15.216",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.148",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.42",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "5.13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "5.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: initialize extack in nh_res_bucket_migrate()\n\nnh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to\ncall_nexthop_res_bucket_notifiers(). When\nnh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns\n-ENOMEM), the error is propagated back before any notifier sets\nextack._msg, and the error path formats the stale pointer with\npr_err_ratelimited(\"%s\\n\", extack._msg). With CONFIG_INIT_STACK_NONE\nthis dereferences uninitialized stack memory:\n\n Oops: general protection fault, probably for non-canonical address ...\n KASAN: maybe wild-memory-access in range [...]\n RIP: 0010:string (lib/vsprintf.c:730)\n vsnprintf (lib/vsprintf.c:2945)\n _printk (kernel/printk/printk.c:2504)\n nh_res_bucket_migrate (net/ipv4/nexthop.c:1816)\n nh_res_table_upkeep (net/ipv4/nexthop.c:1866)\n rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n netlink_sendmsg (net/netlink/af_netlink.c:1900)\n Kernel panic - not syncing: Fatal exception\n\nZero-initialize extack so _msg is NULL on error paths that never set it."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Triggered via local RTM_NEWNEXTHOP over rtnetlink (sendmsg \u2192 rtnetlink_rcv_msg \u2192 rtm_new_nexthop \u2192 nh_res_table_upkeep \u2192 nh_res_bucket_migrate), not by processing remote packets.\nAC:L - An attacker can create resilient nexthop groups, ensure notifiers are registered (e.g. VXLAN pernet init), force bucket migration, and induce the kzalloc -ENOMEM path; stack contents are groomable, with no attacker-independent condition required.\nPR:L - rtnetlink_rcv_msg requires CAP_NET_ADMIN via netlink_net_capable() against the socket netns user_ns, which an unprivileged user obtains with unshare -Urn, so privileges are Low not High.\nUI:N - The attacker issues the netlink nexthop configuration and triggers migration themselves; no victim action is required.\nS:U - Impact stays within the host kernel networking authority; this is a local DoS/disclosure bug, not a VM escape, IOMMU bypass, or other cross-boundary scope change.\nC:H - pr_err_ratelimited(\"%s\") dereferences an uninitialized extack._msg pointer as a C string, enabling an attacker-groomable wild kernel read into the log, consistent with treating unbounded wild/OOB reads as Confidentiality High.\nI:N - The defect only reads through the stale _msg pointer for printing; there is no write, free, or other memory-corruption integrity primitive.\nA:H - The wild %s dereference causes a general protection fault / KASAN wild-memory-access and kernel panic, as shown in the fix commit report, so Availability is High."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:28:57.222Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/eacd2e2117e8682f937967fda1022e7f1c22d91a"
},
{
"url": "https://git.kernel.org/stable/c/37bbd7e1d8df0bec3d187e961783e20c30533d2c"
},
{
"url": "https://git.kernel.org/stable/c/c0936c131a71657afc635d0db2ab096d15d473e1"
},
{
"url": "https://git.kernel.org/stable/c/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d"
},
{
"url": "https://git.kernel.org/stable/c/d536bf205c71f700f6de2086038c3e1d77724715"
},
{
"url": "https://git.kernel.org/stable/c/18506d7263768d76ac8e057ba55a4d9da50aad66"
},
{
"url": "https://git.kernel.org/stable/c/6347c5314cee49f364aaf2e40ff15415a57a116e"
}
],
"title": "nexthop: initialize extack in nh_res_bucket_migrate()",
"x_generator": {
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}
}
},
"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-64576",
"datePublished": "2026-08-05T08:09:32.529Z",
"dateReserved": "2026-07-19T15:36:31.798Z",
"dateUpdated": "2026-08-19T16:28:57.222Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-64576",
"date": "2026-10-01",
"epss": "0.00117",
"percentile": "0.01501"
},
"microsoft_vex": {
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"cve": "CVE-2026-64576",
"id": "msrc_CVE-2026-64576",
"initial_release_date": "2026-08-07T01:19:28.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "nexthop: initialize extack in nh_res_bucket_migrate()",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64576.json",
"version": "2"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv4/nexthop.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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{
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{
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{
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},
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"lessThan": "5.13",
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"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "5.15.216",
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},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.148",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"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\nnexthop: initialize extack in nh_res_bucket_migrate()\n\nnh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to\ncall_nexthop_res_bucket_notifiers(). When\nnh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns\n-ENOMEM), the error is propagated back before any notifier sets\nextack._msg, and the error path formats the stale pointer with\npr_err_ratelimited(\"%s\\n\", extack._msg). With CONFIG_INIT_STACK_NONE\nthis dereferences uninitialized stack memory:\n\n Oops: general protection fault, probably for non-canonical address ...\n KASAN: maybe wild-memory-access in range [...]\n RIP: 0010:string (lib/vsprintf.c:730)\n vsnprintf (lib/vsprintf.c:2945)\n _printk (kernel/printk/printk.c:2504)\n nh_res_bucket_migrate (net/ipv4/nexthop.c:1816)\n nh_res_table_upkeep (net/ipv4/nexthop.c:1866)\n rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n netlink_sendmsg (net/netlink/af_netlink.c:1900)\n Kernel panic - not syncing: Fatal exception\n\nZero-initialize extack so _msg is NULL on error paths that never set it."
}
],
"id": "CVE-2026-64576",
"lastModified": "2026-08-19T17:20:17.540",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.2,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-05T08:16:37.483",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/18506d7263768d76ac8e057ba55a4d9da50aad66"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/37bbd7e1d8df0bec3d187e961783e20c30533d2c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6347c5314cee49f364aaf2e40ff15415a57a116e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c0936c131a71657afc635d0db2ab096d15d473e1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d536bf205c71f700f6de2086038c3e1d77724715"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/eacd2e2117e8682f937967fda1022e7f1c22d91a"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-08-08T16:35:12+00:00",
"cve": "CVE-2026-64576",
"id": "CVE-2026-64576",
"initial_release_date": "2026-08-05T00:00:00+00:00",
"product_status:known_affected": "184",
"product_status:known_not_affected": "90",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: nexthop: initialize extack in nh_res_bucket_migrate()",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64576.json",
"version": "3"
},
"suse_vex": {
"aggregate_severity": "moderate",
"current_release_date": "2026-09-22T16:50:20Z",
"cve": "CVE-2026-64576",
"id": "CVE-2026-64576",
"initial_release_date": "2026-08-06T01:06:19Z",
"product_status:first_fixed": "60",
"product_status:known_affected": "584",
"product_status:known_not_affected": "147",
"product_status:recommended": "111",
"source": "SUSE CSAF VEX",
"status": "interim",
"title": "SUSE CVE CVE-2026-64576",
"url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64576.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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