CVE-2026-97611
📛 CVE Title
net: openvswitch: fix use-after-free of the flow table mask array
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.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- Linux
- CVSS severity
- HIGH
- CVSS score
- 7.8 / 10
- CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Effective score
- 7.8 / 10 HIGH source: CNA overview
- CWE(s)
- —
- Reserved
- 2026-09-24
- Published
- 2026-09-25 10:22 UTC
- Last updated
- 2026-09-25 14:41 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/97xxx/CVE-2026-97611.json
- Linked Threat
- CVE-2026-97611 — net: openvswitch: fix use-after-free of the flow table mask array
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2026-09-25 11:17:15 UTC
- NVD last modified
- 2026-09-25 15:18:01 UTC
- NVD CVSS v3.1
- 7.8 / 10 HIGH source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- NVD CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Exploitability subscore
- 1.8 / 10
- Impact subscore
- 5.9 / 10
NVD / KEV / EPSS data refreshed 2026-09-26 04:25 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
Affected products (2)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Linux | Linux |
eac87c413bf9794c14d488998a5265ea5b32f04e (affected),
eac87c413bf9794c14d488998a5265ea5b32f04e (affected),
eac87c413bf9794c14d488998a5265ea5b32f04e (affected),
eac87c413bf9794c14d488998a5265ea5b32f04e (affected)
|
— |
| Linux | Linux |
5.9 (affected),
0 (unaffected),
6.12.111 (unaffected),
6.18.53 (unaffected),
7.2.7 (unaffected),
7.3-rc3 (unaffected)
|
— |
Vendor references (4)
References embedded in the original CVE record by the assigning CNA.
Web references (0)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
No web references attached yet.
NVD-tagged references (4)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://git.kernel.org/stable/c/035e9c3722067648a99010711d0ce81f42572ef4 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/a0d18d21d48a551f82ee344e50efb8a682161489 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/ba4ba11ed6eb8972c69070417fc27b48deb002e8 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/cd982e11684def5d4a9fcfd5354de09032828414 416baaa9-dc9f-4396-8d5f-8c081fb06d67
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-97611.json.
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/openvswitch/flow_table.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "eac87c413bf9794c14d488998a5265ea5b32f04e",
"versionType": "git"
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{
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"status": "affected",
"version": "eac87c413bf9794c14d488998a5265ea5b32f04e",
"versionType": "git"
},
{
"lessThan": "035e9c3722067648a99010711d0ce81f42572ef4",
"status": "affected",
"version": "eac87c413bf9794c14d488998a5265ea5b32f04e",
"versionType": "git"
},
{
"lessThan": "ba4ba11ed6eb8972c69070417fc27b48deb002e8",
"status": "affected",
"version": "eac87c413bf9794c14d488998a5265ea5b32f04e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/openvswitch/flow_table.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.9"
},
{
"lessThan": "5.9",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.111",
"versionStartIncluding": "5.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.53",
"versionStartIncluding": "5.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.7",
"versionStartIncluding": "5.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3-rc3",
"versionStartIncluding": "5.9",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Both sides of the race are driven locally: tbl_mask_array_realloc() runs from OVS_FLOW_CMD_NEW/DEL generic-netlink requests (flow insert/remove growing or shrinking the mask array), and the reader is ovs_flow_tbl_lookup_stats() fed by the attacker's own packets via internal_dev_xmit. No remote protocol carries data that causes the bug.\nAC:L - The attacker controls both sides, looping flow add/delete to trigger reallocs while transmitting on the datapath's internal port so lookups run. Failed attempts are harmless, the preemptible window can outlast a grace period, and the reporter's KASAN trace shows a PoC hit it.\nPR:L - The OVS datapath, vport and flow genl ops are GENL_UNS_ADMIN_PERM with netnsok=true, so CAP_NET_ADMIN in a user namespace (unshare -Urn) is enough to create a datapath, add flows and send packets through it.\nUI:N - No victim action is needed; the attacker creates the datapath, drives mask-array reallocation and generates the lookup traffic entirely by themselves.\nS:U - The impact stays within the kernel's own security authority, as ordinary kernel memory corruption leading to local privilege escalation; no VM or hardware boundary is crossed.\nC:H - flow_lookup() reads the freed struct mask_array (max, masks[] pointers) and dereferences masks[i] as sw_flow_mask. If the slab is reclaimed with attacker data, that gives controlled-pointer reads of kernel memory.\nI:H - On a flow hit, flow_lookup() does stats->usage_cntrs[index]++ through ma->masks_usage_stats taken from the freed mask_array, so a reclaimed object yields an attacker-steered kernel memory increment (write primitive).\nA:H - The slab use-after-free in flow_lookup() during ovs_dp_process_packet crashes the kernel (KASAN-reported); with a reclaimed object, wild pointer dereferences cause an oops or panic."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-25T14:41:33.156Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/cd982e11684def5d4a9fcfd5354de09032828414"
},
{
"url": "https://git.kernel.org/stable/c/a0d18d21d48a551f82ee344e50efb8a682161489"
},
{
"url": "https://git.kernel.org/stable/c/035e9c3722067648a99010711d0ce81f42572ef4"
},
{
"url": "https://git.kernel.org/stable/c/ba4ba11ed6eb8972c69070417fc27b48deb002e8"
}
],
"title": "net: openvswitch: fix use-after-free of the flow table mask array",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-97611",
"datePublished": "2026-09-25T10:22:20.827Z",
"dateReserved": "2026-09-24T16:01:01.158Z",
"dateUpdated": "2026-09-25T14:41:33.156Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}