CVE-2026-97611

Status: ReceivedHigh (7.8)—

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:

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:

Read full descriptionShow less

Publish the new array before retiring the old one. The kfree_rcu() that call_rcu() replaced ran after the swap.

Technical details traces, logs and code from the original report

	old = ovsl_dereference(tbl->mask_array);
	if (old) {
		...
		call_rcu(&old->rcu, mask_array_rcu_cb);
	}

	rcu_assign_pointer(tbl->mask_array, new);

  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

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.16%
Percentile among all scored CVEs: 4
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Primary impactT1499.004 Application or System Exploitationimpact75 %
Secondary impactT1005 Data from Local Systemcollection60 %

Vulnerabilidad de use-after-free en kernel Linux con privilegios locales (PR:L) permite DoS y lectura de memoria mediante condición de carrera en RCU del módulo openvswitch.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-97611",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
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      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
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              "status": "affected",
              "version": "eac87c413bf9794c14d488998a5265ea5b32f04e",
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              "status": "affected",
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          "programFiles": [
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          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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            {
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver",
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            },
            {
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver",
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              "version": "7.2.7",
              "versionType": "semver",
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            },
            {
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/openvswitch/flow_table.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-25T11:17:15.213",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/017dbbf0d6c319a487f68e22f56d91fc787d5525",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/76678217cdabc41e3c74c23b45b62086ffb8fe7a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cd982e11684def5d4a9fcfd5354de09032828414",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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."
    }
  ],
  "lastModified": "2026-10-03T11:18:07.490",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}