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bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6}

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6} Cilium has a BPF egress gateway feature which forces outgoing K8s Pod traffic to pass through dedicated egress gateways which then SNAT the traffic in order to interact with stable IPs outside the cluster. The traffic is directed to the gateway via vxlan tunnel in collect md mode. A recent BPF change utilized the bpf_redirect_neigh() helper to forward packets after the arrival and decap on vxlan, which turned out over time that the kmalloc-256 slab usage in kernel was ever-increasing. The issue was that vxlan allocates the metadata_dst object and attaches it through a fake dst entry to the skb. The latter was never released though given bpf_redirect_neigh() was merely setting the new dst entry via skb_dst_set() without dropping an existing one first.

Announced Source revision 1
Original source ↗

CVE-2025-40183

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-40183

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "b4ab31414970a7a03a5d55d75083f2c101a30592",
        "lessThan": "3fba965a9aac0fa3cbd8138436a37af9ab466d79",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b4ab31414970a7a03a5d55d75083f2c101a30592",
        "lessThan": "057764172fcc6ee2ccb6c41351a55a9f054dc8fd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b4ab31414970a7a03a5d55d75083f2c101a30592",
        "lessThan": "2e67c2037382abb56497bb9d7b7e10be04eb5598",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b4ab31414970a7a03a5d55d75083f2c101a30592",
        "lessThan": "b6bfe44b6dbb14a31d86c475cdc9c7689534fb09",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "f36a305d30f557306d87c787ddffe094ac5dac89",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "b4ab31414970a7a03a5d55d75083f2c101a30592",
        "lessThan": "7404ce888a45eb7da0508b7cbbe6f2e95302eeb8",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "23f3770e1a53e6c7a553135011f547209e141e72",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/core/filter.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.246",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.195",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.54",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.17.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.17.*"
      },
      {
        "status": "unaffected",
        "version": "6.18",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/core/filter.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-40183

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#30688 · Revision 1
Added to Heist Feed
Publisher date
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