FKIE_CVE-2026-89488

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-10-19 09:17
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: openvswitch: Fix CT limit teardown use-after-free Packet processing uses CT limit state under RCU, while netns teardown frees that state under ovs_mutex. The CT limit pointer was neither removed from readers nor protected by a grace period, allowing packet processing to dereference the freed state. An unprivileged user can trigger this bug from a user and network namespace, causing a slab-use-after-free in ovs_ct_execute() when the netns is torn down. Publish the CT limit pointer through RCU, remove it before teardown, and wait for readers before freeing its contents. Keep ovs_mutex around individual CT limit updates, and use the RCU read-side lock while GET traverses the RCU-protected limit lists. Netns teardown detaches the RCU-protected CT limit state in the pernet .pre_exit callback while holding ovs_mutex. The pernet core guarantees an RCU grace period between the .pre_exit and .exit callbacks, so the .exit callback completes the teardown without adding any extra synchronization. The netlink command handlers do not need NULL checks because the userspace netlink socket holds an active reference to its network namespace while a request is processed. The per-netns exit path therefore cannot run concurrently with SET, DEL, or GET for that socket's namespace.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/conntrack.c",
            "net/openvswitch/conntrack.h",
            "net/openvswitch/datapath.c",
            "net/openvswitch/datapath.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "239f26589a6926db28c436e14f28517581ef1385",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "3b9369881b403f4cdbb11fa998554382bdcc3d8c",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "3b41d907400cc1dd1da9555b81dca422b1f44433",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "680f20d5937fa4d1367c59fe83091b78041015f5",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "bf4aaa7ea2579e24ed7de2e20578a875bebca011",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "e15407c3a8a005324f633cd46cd8fb58042c1157",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "6a6d36fadb8537d9b79e72c9fa51885ec0c33e10",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            },
            {
              "lessThan": "403f96c32c9e24600093d7d0c61c17daeedca957",
              "status": "affected",
              "version": "11efd5cb04a184eea4f57b68ea63dddd463158d1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/conntrack.c",
            "net/openvswitch/conntrack.h",
            "net/openvswitch/datapath.c",
            "net/openvswitch/datapath.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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\nopenvswitch: Fix CT limit teardown use-after-free\n\nPacket processing uses CT limit state under RCU, while netns teardown\nfrees that state under ovs_mutex. The CT limit pointer was neither removed\nfrom readers nor protected by a grace period, allowing packet processing to\ndereference the freed state.\n\nAn unprivileged user can trigger this bug from a user and network\nnamespace, causing a slab-use-after-free in ovs_ct_execute() when the\nnetns is torn down.\n\nPublish the CT limit pointer through RCU, remove it before teardown, and\nwait for readers before freeing its contents. Keep ovs_mutex around\nindividual CT limit updates, and use the RCU read-side lock while GET\ntraverses the RCU-protected limit lists.\n\nNetns teardown detaches the RCU-protected CT limit state in the pernet\n.pre_exit callback while holding ovs_mutex.  The pernet core guarantees an\nRCU grace period between the .pre_exit and .exit callbacks, so the .exit\ncallback completes the teardown without adding any extra synchronization.\n\nThe netlink command handlers do not need NULL checks because the userspace\nnetlink socket holds an active reference to its network namespace while a\nrequest is processed. The per-netns exit path therefore cannot run\nconcurrently with SET, DEL, or GET for that socket\u0027s namespace."
    }
  ],
  "id": "CVE-2026-89488",
  "lastModified": "2026-10-19T09:17:42.480",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-89488",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-16T19:22:48.434691Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-11T20:19:30.557",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/239f26589a6926db28c436e14f28517581ef1385"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3b41d907400cc1dd1da9555b81dca422b1f44433"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3b9369881b403f4cdbb11fa998554382bdcc3d8c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/403f96c32c9e24600093d7d0c61c17daeedca957"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/680f20d5937fa4d1367c59fe83091b78041015f5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6a6d36fadb8537d9b79e72c9fa51885ec0c33e10"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bf4aaa7ea2579e24ed7de2e20578a875bebca011"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e15407c3a8a005324f633cd46cd8fb58042c1157"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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