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ipvs: reset full ip_vs_seq structs in ip_vs_conn_new

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ipvs: reset full ip_vs_seq structs in ip_vs_conn_new Commit 9a05475cebdd ("ipvs: avoid kmem_cache_zalloc in ip_vs_conn_new") changed ip_vs_conn_new() to allocate an ip_vs_conn object with kmem_cache_alloc(). The function then initializes many fields explicitly, but only resets in_seq.delta and out_seq.delta in the two struct ip_vs_seq members. That leaves init_seq and previous_delta uninitialized. This is normally harmless while the corresponding IP_VS_CONN_F_IN_SEQ or IP_VS_CONN_F_OUT_SEQ flag is clear. For connections learned from a sync message, however, ip_vs_proc_conn() preserves those flags from IP_VS_CONN_F_BACKUP_MASK and passes opt=NULL when the message omits IPVS_OPT_SEQ_DATA. In that case the new connection can be hashed with SEQ flags set but with the rest of in_seq/out_seq still containing stale slab data. When a packet for such a connection is later handled by an IPVS application helper, vs_fix_seq() and vs_fix_ack_seq() use previous_delta and init_seq to rewrite TCP sequence numbers. A malformed sync message can therefore make forwarded packets carry stale slab bytes in their TCP seq/ack numbers, and can also corrupt the forwarded TCP flow. Reset both struct ip_vs_seq members completely before publishing the connection. This matches the existing "reset struct ip_vs_seq" comment and keeps the sequence-adjustment gates inactive unless valid sequence data is installed later.

Announced Source revision 1
Original source ↗

CVE-2026-72020

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-2026-72020

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": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "3bf9a260188b2a5449cbddc032a749ab433fe328",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "6378c5cb360eb1750f88839d7c3613ea92ac1816",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "32c299e28b8eea6cbbd23b97dc61401e9ef9c445",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "9e36602cbec552286f7e691cfd366525c565ee74",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "d0eed7177e822cab83141e5c44b2aa345c7fd379",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "83fb4c2c5344f02eac929f66de3c9d1adfcde04c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "6335ab62d5fc9ed875279238233fba3462c168f5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9a05475cebdd6341884b5901e53870be26e65158",
        "lessThan": "2975324d164c552b028632f107b567302863b7f6",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/netfilter/ipvs/ip_vs_conn.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/netfilter/ipvs/ip_vs_conn.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72020

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#41839 · Revision 1
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Publisher date
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