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netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation Ulrich reports a regression with nfqueue: If an application did not set the 'F_GSO' capability flag and a gso packet with an unconfirmed nf_conn entry is received all packets are now dropped instead of queued, because the check happens after skb_gso_segment(). In that case, we did have exclusive ownership of the skb and its associated conntrack entry. The elevated use count is due to skb_clone happening via skb_gso_segment(). Move the check so that its peformed vs. the aggregated packet. Then, annotate the individual segments except the first one so we can do a 2nd check at reinject time. For the normal case, where userspace does in-order reinjects, this avoids packet drops: first reinjected segment continues traversal and confirms entry, remaining segments observe the confirmed entry. While at it, simplify nf_ct_drop_unconfirmed(): We only care about unconfirmed entries with a refcnt > 1, there is no need to special-case dying entries. This only happens with UDP. With TCP, the only unconfirmed packet will be the TCP SYN, those aren't aggregated by GRO. Next patch adds a udpgro test case to cover this scenario.

Announced Source revision 1
Original source ↗

CVE-2026-45859

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-2026-45859

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": "74e6eb7fd27ef1ccc68041dbc66e6d80d2e4a1a0",
        "lessThan": "aead84bdacd77e08357fd718e5dcaffaf387f3c3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb",
        "lessThan": "79b713ef4261a8ead96af4703f89d0b5f25532e2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb",
        "lessThan": "23901aa6b8a2f294c4b774436b4691f3ff863a8f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb",
        "lessThan": "b740e7ddd7ca0dbfeafca3f5e52717206cf28524",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb",
        "lessThan": "207b3ebacb6113acaaec0d171d5307032c690004",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6c4a0ba674f410ab99a30a16f32dac0ebfed5cd3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6dcc8ba8a6074bb79040f502dc66ad23a58a1c86",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "025b3326c5c409b372d0103ad30f174e55adbd1b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.6.48",
        "lessThan": "6.6.160",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "5.15.166",
        "lessThan": "5.16",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.107",
        "lessThan": "6.2",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.10.7",
        "lessThan": "6.11",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "include/net/netfilter/nf_queue.h",
      "net/netfilter/nfnetlink_queue.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.11"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.11",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.75",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.14",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/netfilter/nf_queue.h",
      "net/netfilter/nfnetlink_queue.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-45859

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#46303 · Revision 1
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Publisher date
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