CVE-2026-97611
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix use-after-free of the flow table mask array tbl_mask_array_realloc() retires the old mask_array before it stops being reachable: old = ovsl_dereference(tbl->mask_array); if (old) { ... call_rcu(&old->rcu, mask_array_rcu_cb); } rcu_assign_pointer(tbl->mask_array, new); call_rcu() only waits for read-side critical sections already in flight. tbl->mask_array still points at old between the call_rcu() and the rcu_assign_pointer(), so a reader entering ovs_flow_tbl_lookup_stats() in that window picks up old in a fresh critical section that the pending grace period does not cover. tbl_mask_array_realloc() runs in process context under ovs_mutex, so the window is preemptible and can outlast the grace period. Then mask_array_rcu_cb() frees old before the swap runs: BUG: KASAN: slab-use-after-free in flow_lookup.constprop.0+0x2bf/0x2f0 Read of size 8 at addr ffff888020b3e018 by task poc/741 flow_lookup.constprop.0+0x2bf/0x2f0 ovs_flow_tbl_lookup_stats+0x4a3/0x5c0 ovs_dp_process_packet+0x19c/0x710 ovs_vport_receive+0x243/0x390 internal_dev_xmit+0x81/0x170 Freed by task 728: kfree+0x16a/0x4e0 rcu_core+0x853/0x1030 Publish the new array before retiring the old one. The kfree_rcu() that call_rcu() replaced ran after the swap.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-09-25 11:17:15.213000
Last modified
2026-10-19 10:17:31.140000
View original CVE JSON
{
"id": "CVE-2026-97611",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-25T11:17:15.213",
"lastModified": "2026-10-19T10:17:31.140",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: fix use-after-free of the flow table mask array\n\ntbl_mask_array_realloc() retires the old mask_array before it stops being\nreachable:\n\n\told = ovsl_dereference(tbl->mask_array);\n\tif (old) {\n\t\t...\n\t\tcall_rcu(&old->rcu, mask_array_rcu_cb);\n\t}\n\n\trcu_assign_pointer(tbl->mask_array, new);\n\ncall_rcu() only waits for read-side critical sections already in flight.\ntbl->mask_array still points at old between the call_rcu() and the\nrcu_assign_pointer(), so a reader entering ovs_flow_tbl_lookup_stats() in\nthat window picks up old in a fresh critical section that the pending\ngrace period does not cover.\n\ntbl_mask_array_realloc() runs in process context under ovs_mutex, so the\nwindow is preemptible and can outlast the grace period. Then\nmask_array_rcu_cb() frees old before the swap runs:\n\n BUG: KASAN: slab-use-after-free in flow_lookup.constprop.0+0x2bf/0x2f0\n Read of size 8 at addr ffff888020b3e018 by task poc/741\n flow_lookup.constprop.0+0x2bf/0x2f0\n ovs_flow_tbl_lookup_stats+0x4a3/0x5c0\n ovs_dp_process_packet+0x19c/0x710\n ovs_vport_receive+0x243/0x390\n internal_dev_xmit+0x81/0x170\n Freed by task 728:\n kfree+0x16a/0x4e0\n rcu_core+0x853/0x1030\n\nPublish the new array before retiring the old one. The kfree_rcu() that\ncall_rcu() replaced ran after the swap."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/openvswitch/flow_table.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
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"status": "affected"
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},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/openvswitch/flow_table.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.9",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.9",
"versionType": "semver",
"status": "unaffected"
},
{
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"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.222",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.189",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.158",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.111",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.53",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.7",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
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}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
]
},
"references": [
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"url": "https://git.kernel.org/stable/c/017dbbf0d6c319a487f68e22f56d91fc787d5525",
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}