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net/sched: cls_u32: fix duplicate handle when node ID pool is exhausted

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_u32: fix duplicate handle when node ID pool is exhausted gen_new_kid() falls back to returning max (htid | 0xFFF) when both idr_alloc_u32() ranges are full, instead of reporting an error. u32_change() trusts that value and inserts a new knode with a handle that is already live in the hash table, breaking handle uniqueness within the table's node ID space. The handle was never reserved in ht->handle_idr, so every later error path that does idr_remove(&ht->handle_idr, handle) removes the reservation of a different, live knode, which is then reused — one failed add compounds into further duplicates. The 4095 limit is per (table, bucket) — ht->handle_idr is per hash table and the range is derived from htid (bucketid), so a table with divisor 256 can legitimately hold 256*4095 knodes. The sibling helper gen_new_htid() has the same silent in-band failure: it returns 0 when the tp_c handle pool (1..0x7FF) is full, and u32_init() publishes the root hash table with handle 0 without checking. Two root tables with handle 0 alias in u32_lookup_ht(), allowing cross-tcf_proto knode add/lookup/delete. Add the same exhaustion check that the divisor path already has. Return an error so u32_change() fails with ENOSPC/ENOMEM when the node ID space is exhausted, and so u32_init() fails with -ENOMEM when the hash table ID space is exhausted. The extack message distinguishes pool exhaustion (-ENOSPC) from a transien

Announced Source revision 1
Original source ↗

CVE-2026-98104

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-2026-98104

Linux

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

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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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": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "f4ee13ed7f7b22dcd8287fcf477ae37bd84567da",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "84223baf21bc9b008444ae9bc38d5fb91fe00b9d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "6890e28840bae4f6805e8de981c4ec8e12a4e064",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "feab9261b537df4ebb8350e4779bc185373059fd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "f594f04268d01c5fdc975f3f51fc219ea2159ac6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7801db8aec957fa6610efe0ee26a6c8bc0f1d73b",
        "lessThan": "d7e7e98d23f42a92d9ab7e36302bd96bd9b33b5f",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sched/cls_u32.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.16"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.16",
        "versionType": "semver"
      },
      {
        "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",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/cls_u32.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98104

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38204 · Revision 1
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Publisher date
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