CVE-2026-97939 (GCVE-0-2026-97939)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 10:22
VLAI
Title
ipmr: account multicast table and route memory
Summary
In the Linux kernel, the following vulnerability has been resolved: ipmr: account multicast table and route memory A netadmin in a user+net namespace can create many IPv4 and IPv6 multicast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen id allocates an mr_table via the shared mr_table_alloc(), links it into the per-net list, and leaves it until netns teardown. Those objects were not charged to memcg, so the host unreclaimable slab grows with the table count. Account mr_table allocations with GFP_KERNEL_ACCOUNT and mark the IPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established handling of IP addresses, routes and alternate interface names. Unresolved MFC entries are still allocated from softIRQ with GFP_ATOMIC and are not charged. They expire after 10 seconds and are bounded by the socket receive queue; see commit 0079ad8e8dc3 ("ipmr: remove hard code cache_resolve_queue_len limit").
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f0ad0860d01e47a3ffd220564c5c653b3afbe962 , < 0264b3ee09b118fec8a5471b4ca288f8ab84722f (git)
Affected: f0ad0860d01e47a3ffd220564c5c653b3afbe962 , < d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c (git)
Affected: f0ad0860d01e47a3ffd220564c5c653b3afbe962 , < b7ee18725f2292ab554aa96a101ae42d45f008bd (git)
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Linux Linux Affected: 2.6.35
Unaffected: 0 , < 2.6.35 (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/ipmr.c",
            "net/ipv4/ipmr_base.c",
            "net/ipv6/ip6mr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "versions": [
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          "nodes": [
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmr: account multicast table and route memory\n\nA netadmin in a user+net namespace can create many IPv4 and IPv6\nmulticast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen\nid allocates an mr_table via the shared mr_table_alloc(), links it\ninto the per-net list, and leaves it until netns teardown. Those\nobjects were not charged to memcg, so the host unreclaimable slab\ngrows with the table count.\n\nAccount mr_table allocations with GFP_KERNEL_ACCOUNT and mark the\nIPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established\nhandling of IP addresses, routes and alternate interface names.\n\nUnresolved MFC entries are still allocated from softIRQ with\nGFP_ATOMIC and are not charged. They expire after 10 seconds and are\nbounded by the socket receive queue; see commit 0079ad8e8dc3\n(\"ipmr: remove hard code cache_resolve_queue_len limit\")."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T10:22:52.332Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/0264b3ee09b118fec8a5471b4ca288f8ab84722f"
        },
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        },
        {
          "url": "https://git.kernel.org/stable/c/b7ee18725f2292ab554aa96a101ae42d45f008bd"
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      ],
      "title": "ipmr: account multicast table and route memory",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97939",
    "datePublished": "2026-09-25T10:22:52.332Z",
    "dateReserved": "2026-09-25T10:18:58.204Z",
    "dateUpdated": "2026-09-25T10:22:52.332Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-28",
      "epss": "0.00198",
      "percentile": "0.08572"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-28T01:42:18.000Z",
      "cve": "CVE-2026-97939",
      "id": "msrc_CVE-2026-97939",
      "initial_release_date": "2026-09-28T00:23:36.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ipmr: account multicast table and route memory",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-97939.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
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                  "net/ipv4/ipmr_base.c",
                  "net/ipv6/ip6mr.c"
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "status": "unaffected",
                    "version": "7.2.7",
                    "versionType": "semver"
                  },
                  {
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              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipmr: account multicast table and route memory\n\nA netadmin in a user+net namespace can create many IPv4 and IPv6\nmulticast routing tables with MRT_TABLE and MRT6_TABLE. Each unseen\nid allocates an mr_table via the shared mr_table_alloc(), links it\ninto the per-net list, and leaves it until netns teardown. Those\nobjects were not charged to memcg, so the host unreclaimable slab\ngrows with the table count.\n\nAccount mr_table allocations with GFP_KERNEL_ACCOUNT and mark the\nIPv4/IPv6 MFC caches SLAB_ACCOUNT. This matches the established\nhandling of IP addresses, routes and alternate interface names.\n\nUnresolved MFC entries are still allocated from softIRQ with\nGFP_ATOMIC and are not charged. They expire after 10 seconds and are\nbounded by the socket receive queue; see commit 0079ad8e8dc3\n(\"ipmr: remove hard code cache_resolve_queue_len limit\")."
          }
        ],
        "id": "CVE-2026-97939",
        "lastModified": "2026-09-25T11:17:21.303",
        "metrics": {},
        "published": "2026-09-25T11:17:21.303",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0264b3ee09b118fec8a5471b4ca288f8ab84722f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/d0a2e2a4ee6bfe51e398bfb6921a7d0f4c26bc1c"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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