Vulnerability-Lookup

GHSA-RHCJ-6WXJ-R34P

Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-08 15:31

Details

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.

Severity ?

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-43198"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-06T12:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix potential race in tcp_v6_syn_recv_sock()\n\nCode in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock()\nis done too late.\n\nAfter tcp_v4_syn_recv_sock(), the child socket is already visible\nfrom TCP ehash table and other cpus might use it.\n\nSince newinet-\u003epinet6 is still pointing to the listener ipv6_pinfo\nbad things can happen as syzbot found.\n\nMove the problematic code in tcp_v6_mapped_child_init()\nand call this new helper from tcp_v4_syn_recv_sock() before\nthe ehash insertion.\n\nThis allows the removal of one tcp_sync_mss(), since\ntcp_v4_syn_recv_sock() will call it with the correct\ncontext.",
  "id": "GHSA-rhcj-6wxj-r34p",
  "modified": "2026-05-08T15:31:17Z",
  "published": "2026-05-06T12:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43198"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-43198 (GCVE-0-2026-43198)

Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-05-11 22:19

Title

tcp: fix potential race in tcp_v6_syn_recv_sock()

Summary

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.

Severity ?

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/fe89b2f05b8548477…
https://git.kernel.org/stable/c/7178e2a8027423b2a…
https://git.kernel.org/stable/c/858d2a4f67ff69e64…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < fe89b2f05b854847784f91127319172945c1fadd (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7178e2a8027423b2af17ab95df73a749a5b72e5b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 858d2a4f67ff69e645a43487ef7ea7f28f06deae (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 6.18.16 , ≤ 6.18.* (semver) Unaffected: 6.19.6 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "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"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fe89b2f05b854847784f91127319172945c1fadd",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7178e2a8027423b2af17ab95df73a749a5b72e5b",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "858d2a4f67ff69e645a43487ef7ea7f28f06deae",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "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"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.16",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.6",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "2.6.12",
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                }
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              "negate": false,
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix potential race in tcp_v6_syn_recv_sock()\n\nCode in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock()\nis done too late.\n\nAfter tcp_v4_syn_recv_sock(), the child socket is already visible\nfrom TCP ehash table and other cpus might use it.\n\nSince newinet-\u003epinet6 is still pointing to the listener ipv6_pinfo\nbad things can happen as syzbot found.\n\nMove the problematic code in tcp_v6_mapped_child_init()\nand call this new helper from tcp_v4_syn_recv_sock() before\nthe ehash insertion.\n\nThis allows the removal of one tcp_sync_mss(), since\ntcp_v4_syn_recv_sock() will call it with the correct\ncontext."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:19:44.515Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/fe89b2f05b854847784f91127319172945c1fadd"
        },
        {
          "url": "https://git.kernel.org/stable/c/7178e2a8027423b2af17ab95df73a749a5b72e5b"
        },
        {
          "url": "https://git.kernel.org/stable/c/858d2a4f67ff69e645a43487ef7ea7f28f06deae"
        }
      ],
      "title": "tcp: fix potential race in tcp_v6_syn_recv_sock()",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43198",
    "datePublished": "2026-05-06T11:28:05.569Z",
    "dateReserved": "2026-05-01T14:12:55.992Z",
    "dateUpdated": "2026-05-11T22:19:44.515Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-RHCJ-6WXJ-R34P

CVE-2026-43198 (GCVE-0-2026-43198)

Tags

Sightings

Nomenclature