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CVE-2026-53220

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: revalidate bridge ports ebt_redirect_tg() dereferences br_port_get_rcu() return without a NULL check, causing a kernel panic when the bridge port has been removed between the original hook invocation and an NFQUEUE reinject. A mere NULL check isn't sufficient, however. As sashiko review points out userspace can not only remove the port from the bridge, it could also place the device in a different virtual device, e.g. macvlan. If this happens, we must drop the packet, there is no way for us to reinject it into the bridge path. Switch to _upper API, we don't need the bridge port structure. Also, this fix keeps another bug intact: Both nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER too aggressive, which prevents certain logging features when queueing in bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old CONFIG_BRIDGE_NETFILTER cruft is off. Fixes tag is a common ancestor, this was always broken.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-25 09:16:39.743000
Last modified
2026-10-30 13:19:11.617000
View original CVE JSON 
{
  "id": "CVE-2026-53220",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-25T09:16:39.743",
  "lastModified": "2026-10-30T13:19:11.617",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: revalidate bridge ports\n\nebt_redirect_tg() dereferences br_port_get_rcu() return without a\nNULL check, causing a kernel panic when the bridge port has been\nremoved between the original hook invocation and an NFQUEUE\nreinject.\n\nA mere NULL check isn't sufficient, however.  As sashiko review\npoints out userspace can not only remove the port from the bridge,\nit could also place the device in a different virtual device, e.g.\nmacvlan.\n\nIf this happens, we must drop the packet, there is no way for us to\nreinject it into the bridge path.\n\nSwitch to _upper API, we don't need the bridge port structure.\nAlso, this fix keeps another bug intact:\n\nBoth nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER\ntoo aggressive, which prevents certain logging features when queueing\nin bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old\nCONFIG_BRIDGE_NETFILTER cruft is off.\n\nFixes tag is a common ancestor, this was always broken."
    }
  ],
  "affected": [
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      "affectedData": [
        {
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          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/bridge/netfilter/ebt_dnat.c",
            "net/bridge/netfilter/ebt_redirect.c",
            "net/netfilter/nfnetlink_log.c",
            "net/netfilter/nfnetlink_queue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "defaultStatus": "affected",
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            "net/bridge/netfilter/ebt_redirect.c",
            "net/netfilter/nfnetlink_log.c",
            "net/netfilter/nfnetlink_queue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "status": "unaffected"
            },
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              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.94",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.36",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
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            },
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              "version": "7.1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
  ],
  "configurations": [
    {
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          "negate": false,
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  "references": [
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      "url": "https://git.kernel.org/stable/c/43330a1e8aace6b5a8de9aba127e9e394ab49b0f",
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}