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GHSA-XJQR-QMX4-H4W3

Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-28 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)

do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the get_info function pointer without rcu_read_lock(). With BPF struct_ops congestion control, ca_ops can point to dynamically allocated memory that is freed concurrently, resulting in a use-after-free when the kernel dereferences or calls through the stale pointer.

BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0 Read of size 8 at addr ffff888013701258 by task exploit/149 do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170

Fix this by wrapping the ca_ops load and get_info call within rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load the icsk_ca_ops pointer.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99138"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T11:17:33Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)\n\ndo_tcp_getsockopt() reads icsk-\u003eicsk_ca_ops and dereferences the\nget_info function pointer without rcu_read_lock(). With BPF struct_ops\ncongestion control, ca_ops can point to dynamically allocated memory\nthat is freed concurrently, resulting in a use-after-free when the\nkernel dereferences or calls through the stale pointer.\n\n  BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0\n  Read of size 8 at addr ffff888013701258 by task exploit/149\n   do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by wrapping the ca_ops load and get_info call within\nrcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load\nthe icsk_ca_ops pointer.",
  "id": "GHSA-xjqr-qmx4-h4w3",
  "modified": "2026-10-28T12:31:04Z",
  "published": "2026-10-28T12:31:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99138"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86814e5370068ec2bf0caa6e6d55c3e5bfc6c324"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99138 (GCVE-0-2026-99138)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:34 – Updated: 2026-10-28 10:34

Title

tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)

Summary

In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO) do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the get_info function pointer without rcu_read_lock(). With BPF struct_ops congestion control, ca_ops can point to dynamically allocated memory that is freed concurrently, resulting in a use-after-free when the kernel dereferences or calls through the stale pointer. BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0 Read of size 8 at addr ffff888013701258 by task exploit/149 do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by wrapping the ca_ops load and get_info call within rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load the icsk_ca_ops pointer.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7033 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/86814e5370068ec2b…
https://git.kernel.org/stable/c/39aa489e85752f9de…
https://git.kernel.org/stable/c/385e474086c2e7e29…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 86814e5370068ec2bf0caa6e6d55c3e5bfc6c324 (git) Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 39aa489e85752f9de214edb0f85e4d578e57af29 (git) Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 385e474086c2e7e29e2dded690be40dc273e20ee (git)
Linux	Linux	Affected: 5.6 Unaffected: 0 , < 5.6 (semver) Unaffected: 6.18.59 , ≤ 6.18.* (semver) Unaffected: 7.2.13 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_dctcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "86814e5370068ec2bf0caa6e6d55c3e5bfc6c324",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "39aa489e85752f9de214edb0f85e4d578e57af29",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "385e474086c2e7e29e2dded690be40dc273e20ee",
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        },
        {
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.59",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.59",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
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                },
                {
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                }
              ],
              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)\n\ndo_tcp_getsockopt() reads icsk-\u003eicsk_ca_ops and dereferences the\nget_info function pointer without rcu_read_lock(). With BPF struct_ops\ncongestion control, ca_ops can point to dynamically allocated memory\nthat is freed concurrently, resulting in a use-after-free when the\nkernel dereferences or calls through the stale pointer.\n\n  BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0\n  Read of size 8 at addr ffff888013701258 by task exploit/149\n   do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by wrapping the ca_ops load and get_info call within\nrcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load\nthe icsk_ca_ops pointer."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-28T10:34:49.993Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29"
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        {
          "url": "https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee"
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      ],
      "title": "tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)",
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  "cveMetadata": {
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    "datePublished": "2026-10-28T10:34:49.993Z",
    "dateReserved": "2026-09-25T10:25:14.395Z",
    "dateUpdated": "2026-10-28T10:34:49.993Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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