CVE-2026-99139 (GCVE-0-2026-99139)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:34 – Updated: 2026-10-30 12:42
VLAI
Title
tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)
Summary
In the Linux kernel, the following vulnerability has been resolved: tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION) do_tcp_getsockopt() reads icsk->icsk_ca_ops->name without holding rcu_read_lock(). Since commit 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf"), icsk_ca_ops can point to dynamically allocated BPF struct_ops memory that may be freed concurrently via setsockopt(TCP_CONGESTION), leading to a use-after-free. BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60 Read of size 16 at addr ffff888013505260 by task exploit/149 _copy_to_user+0x37/0x60 do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585) tcp_getsockopt+0x91/0xf0 __sys_getsockopt+0xf7/0x170 Fix this by holding rcu_read_lock() around the ca_ops->name access, using READ_ONCE() to load icsk_ca_ops, and copying the name to a stack buffer before releasing the lock. Also annotate the relevant icsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN data-race issue.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6637 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < a60e62705c17534d6b6539de7b3a40c259e6827f (git)
Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03 (git)
Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 08dc5c62c09653d1c4ba67a009beb138486c2604 (git)
Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < c1804ef016392dd91267d2207ee43b1de34302ca (git)
Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < a8e45471afa230c1431c26c8e99ec24377e3b514 (git)
Affected: 0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2 , < 5271b79b7ad68dcb222e893773f92bdabf7750f3 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.6
Unaffected: 0 , < 5.6 (semver)
Unaffected: 6.1.191 , ≤ 6.1.* (semver)
Unaffected: 6.6.161 , ≤ 6.6.* (semver)
Unaffected: 6.12.115 , ≤ 6.12.* (semver)
Unaffected: 6.18.59 , ≤ 6.18.* (semver)
Unaffected: 7.2.13 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_cong.c",
            "net/ipv4/tcp_dctcp.c",
            "net/ipv4/tcp_minisocks.c",
            "net/ipv4/tcp_output.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a60e62705c17534d6b6539de7b3a40c259e6827f",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "08dc5c62c09653d1c4ba67a009beb138486c2604",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "c1804ef016392dd91267d2207ee43b1de34302ca",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "a8e45471afa230c1431c26c8e99ec24377e3b514",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            },
            {
              "lessThan": "5271b79b7ad68dcb222e893773f92bdabf7750f3",
              "status": "affected",
              "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_cong.c",
            "net/ipv4/tcp_dctcp.c",
            "net/ipv4/tcp_minisocks.c",
            "net/ipv4/tcp_output.c"
          ],
          "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": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.161",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.115",
              "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",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.191",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.161",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.115",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.59",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.13",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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_CONGESTION)\n\ndo_tcp_getsockopt() reads icsk-\u003eicsk_ca_ops-\u003ename without holding\nrcu_read_lock(). Since commit 0baf26b0fcd7 (\"bpf: tcp: Support\ntcp_congestion_ops in bpf\"), icsk_ca_ops can point to dynamically\nallocated BPF struct_ops memory that may be freed concurrently via\nsetsockopt(TCP_CONGESTION), leading to a use-after-free.\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60\n  Read of size 16 at addr ffff888013505260 by task exploit/149\n   _copy_to_user+0x37/0x60\n   do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by holding rcu_read_lock() around the ca_ops-\u003ename access,\nusing READ_ONCE() to load icsk_ca_ops, and copying the name to a\nstack buffer before releasing the lock. Also annotate the relevant\nicsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN\ndata-race issue."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:42:11.824Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a60e62705c17534d6b6539de7b3a40c259e6827f"
        },
        {
          "url": "https://git.kernel.org/stable/c/4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03"
        },
        {
          "url": "https://git.kernel.org/stable/c/08dc5c62c09653d1c4ba67a009beb138486c2604"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1804ef016392dd91267d2207ee43b1de34302ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/a8e45471afa230c1431c26c8e99ec24377e3b514"
        },
        {
          "url": "https://git.kernel.org/stable/c/5271b79b7ad68dcb222e893773f92bdabf7750f3"
        }
      ],
      "title": "tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99139",
    "datePublished": "2026-10-28T10:34:50.674Z",
    "dateReserved": "2026-09-25T10:25:14.395Z",
    "dateUpdated": "2026-10-30T12:42:11.824Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-99139",
      "date": "2026-11-05",
      "epss": "0.00173",
      "percentile": "0.06796"
    },
    "microsoft_vex": {
      "current_release_date": "2026-11-01T14:50:00.000Z",
      "cve": "CVE-2026-99139",
      "id": "msrc_CVE-2026-99139",
      "initial_release_date": "2026-10-29T01:05:21.000Z",
      "product_status:known_affected": "2",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "tcp: fix use-after-free in do_tcp_getsockopt(TCP_CONGESTION)",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-99139.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/ipv4/tcp.c",
                  "net/ipv4/tcp_cong.c",
                  "net/ipv4/tcp_dctcp.c",
                  "net/ipv4/tcp_minisocks.c",
                  "net/ipv4/tcp_output.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "a60e62705c17534d6b6539de7b3a40c259e6827f",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "08dc5c62c09653d1c4ba67a009beb138486c2604",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c1804ef016392dd91267d2207ee43b1de34302ca",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a8e45471afa230c1431c26c8e99ec24377e3b514",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5271b79b7ad68dcb222e893773f92bdabf7750f3",
                    "status": "affected",
                    "version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/ipv4/tcp.c",
                  "net/ipv4/tcp_cong.c",
                  "net/ipv4/tcp_dctcp.c",
                  "net/ipv4/tcp_minisocks.c",
                  "net/ipv4/tcp_output.c"
                ],
                "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": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.191",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.161",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.115",
                    "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",
                    "version": "7.3",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "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_CONGESTION)\n\ndo_tcp_getsockopt() reads icsk-\u003eicsk_ca_ops-\u003ename without holding\nrcu_read_lock(). Since commit 0baf26b0fcd7 (\"bpf: tcp: Support\ntcp_congestion_ops in bpf\"), icsk_ca_ops can point to dynamically\nallocated BPF struct_ops memory that may be freed concurrently via\nsetsockopt(TCP_CONGESTION), leading to a use-after-free.\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user+0x37/0x60\n  Read of size 16 at addr ffff888013505260 by task exploit/149\n   _copy_to_user+0x37/0x60\n   do_tcp_getsockopt+0x158a/0x2460 (net/ipv4/tcp.c:4585)\n   tcp_getsockopt+0x91/0xf0\n   __sys_getsockopt+0xf7/0x170\n\nFix this by holding rcu_read_lock() around the ca_ops-\u003ename access,\nusing READ_ONCE() to load icsk_ca_ops, and copying the name to a\nstack buffer before releasing the lock. Also annotate the relevant\nicsk_ca_ops stores with WRITE_ONCE() to fix the accompanying KCSAN\ndata-race issue."
          }
        ],
        "id": "CVE-2026-99139",
        "lastModified": "2026-10-30T13:21:48.150",
        "metrics": {},
        "published": "2026-10-28T11:17:33.850",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/08dc5c62c09653d1c4ba67a009beb138486c2604"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/4b0930d66dde0a1d1898f0edbbb5496c4dfa5f03"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5271b79b7ad68dcb222e893773f92bdabf7750f3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/a60e62705c17534d6b6539de7b3a40c259e6827f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/a8e45471afa230c1431c26c8e99ec24377e3b514"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c1804ef016392dd91267d2207ee43b1de34302ca"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-30T06:33:19+00:00",
      "cve": "CVE-2026-99139",
      "id": "CVE-2026-99139",
      "initial_release_date": "2026-10-28T10:34:50.674000+00:00",
      "product_status:known_affected": "251",
      "product_status:known_not_affected": "28",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: kernel: privilege escalation via use-after-free in do_tcp_getsockopt",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-99139.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.