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tcp: fix potential race in tcp_v6_syn_recv_sock()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: tcp: fix potential race in tcp_v6_syn_recv_sock() Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

Announced Source revision 1
Original source ↗

CVE-2026-43198

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-2026-43198

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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "aef4a9ae95d1bc4f7897065011e6261026719aeb",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "dad1fe7db6c6519138430ac8f5e589c18f83bfc9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "a7e761ba55efaa9c49e0afdd304bb78167af3429",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "cd644e6dc72eec8d9d988717ea1c54f8668ded69",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "9ed654e340f4c73bc6f0af2fbc90ac293e645ce0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "fe89b2f05b854847784f91127319172945c1fadd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "7178e2a8027423b2af17ab95df73a749a5b72e5b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
        "lessThan": "858d2a4f67ff69e645a43487ef7ea7f28f06deae",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/inet_connection_sock.h",
      "include/net/tcp.h",
      "net/ipv4/syncookies.c",
      "net/ipv4/tcp_fastopen.c",
      "net/ipv4/tcp_ipv4.c",
      "net/ipv4/tcp_minisocks.c",
      "net/ipv6/tcp_ipv6.c",
      "net/mptcp/subflow.c",
      "net/smc/af_smc.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.270",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.16",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.6",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/inet_connection_sock.h",
      "include/net/tcp.h",
      "net/ipv4/syncookies.c",
      "net/ipv4/tcp_fastopen.c",
      "net/ipv4/tcp_ipv4.c",
      "net/ipv4/tcp_minisocks.c",
      "net/ipv6/tcp_ipv6.c",
      "net/mptcp/subflow.c",
      "net/smc/af_smc.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-43198

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#40043 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement