CVE-2025-68775 (GCVE-0-2025-68775)

Vulnerability from cvelistv5 – Published: 2026-01-13 15:28 – Updated: 2026-05-11 21:53
VLAI
Title
net/handshake: duplicate handshake cancellations leak socket
Summary
In the Linux kernel, the following vulnerability has been resolved: net/handshake: duplicate handshake cancellations leak socket When a handshake request is cancelled it is removed from the handshake_net->hn_requests list, but it is still present in the handshake_rhashtbl until it is destroyed. If a second cancellation request arrives for the same handshake request, then remove_pending() will return false... and assuming HANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue processing through the out_true label, where we put another reference on the sock and a refcount underflow occurs. This can happen for example if a handshake times out - particularly if the SUNRPC client sends the AUTH_TLS probe to the server but doesn't follow it up with the ClientHello due to a problem with tlshd. When the timeout is hit on the server, the server will send a FIN, which triggers a cancellation request via xs_reset_transport(). When the timeout is hit on the client, another cancellation request happens via xs_tls_handshake_sync(). Add a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel path so duplicate cancels can be detected.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 3b3009ea8abb713b022d94fba95ec270cf6e7eae , < 011ae80c49d9bfa5b4336f8bd387cd25c7593663 (git)
Affected: 3b3009ea8abb713b022d94fba95ec270cf6e7eae , < e1641177e7fb48a0a5a06658d4aab51da6656659 (git)
Affected: 3b3009ea8abb713b022d94fba95ec270cf6e7eae , < 3c330f1dee3cd92b57e19b9d21dc8ce5970b09be (git)
Affected: 3b3009ea8abb713b022d94fba95ec270cf6e7eae , < 15564bd67e2975002f2a8e9defee33e321d3183f (git)
Create a notification for this product.
Linux Linux Affected: 6.4
Unaffected: 0 , < 6.4 (semver)
Unaffected: 6.6.120 , ≤ 6.6.* (semver)
Unaffected: 6.12.64 , ≤ 6.12.* (semver)
Unaffected: 6.18.3 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/handshake/request.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "011ae80c49d9bfa5b4336f8bd387cd25c7593663",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "e1641177e7fb48a0a5a06658d4aab51da6656659",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "3c330f1dee3cd92b57e19b9d21dc8ce5970b09be",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            },
            {
              "lessThan": "15564bd67e2975002f2a8e9defee33e321d3183f",
              "status": "affected",
              "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/handshake/request.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "lessThan": "6.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.120",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.120",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.64",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.3",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19",
                  "versionStartIncluding": "6.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: duplicate handshake cancellations leak socket\n\nWhen a handshake request is cancelled it is removed from the\nhandshake_net-\u003ehn_requests list, but it is still present in the\nhandshake_rhashtbl until it is destroyed.\n\nIf a second cancellation request arrives for the same handshake request,\nthen remove_pending() will return false... and assuming\nHANDSHAKE_F_REQ_COMPLETED isn\u0027t set in req-\u003ehr_flags, we\u0027ll continue\nprocessing through the out_true label, where we put another reference on\nthe sock and a refcount underflow occurs.\n\nThis can happen for example if a handshake times out - particularly if\nthe SUNRPC client sends the AUTH_TLS probe to the server but doesn\u0027t\nfollow it up with the ClientHello due to a problem with tlshd.  When the\ntimeout is hit on the server, the server will send a FIN, which triggers\na cancellation request via xs_reset_transport().  When the timeout is\nhit on the client, another cancellation request happens via\nxs_tls_handshake_sync().\n\nAdd a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel\npath so duplicate cancels can be detected."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:53:06.843Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663"
        },
        {
          "url": "https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be"
        },
        {
          "url": "https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f"
        }
      ],
      "title": "net/handshake: duplicate handshake cancellations leak socket",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68775",
    "datePublished": "2026-01-13T15:28:52.069Z",
    "dateReserved": "2025-12-24T10:30:51.035Z",
    "dateUpdated": "2026-05-11T21:53:06.843Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68775",
      "date": "2026-07-27",
      "epss": "0.00168",
      "percentile": "0.06417"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-68775\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-13T16:15:57.073\",\"lastModified\":\"2026-06-17T09:59:34.077\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet/handshake: duplicate handshake cancellations leak socket\\n\\nWhen a handshake request is cancelled it is removed from the\\nhandshake_net-\u003ehn_requests list, but it is still present in the\\nhandshake_rhashtbl until it is destroyed.\\n\\nIf a second cancellation request arrives for the same handshake request,\\nthen remove_pending() will return false... and assuming\\nHANDSHAKE_F_REQ_COMPLETED isn\u0027t set in req-\u003ehr_flags, we\u0027ll continue\\nprocessing through the out_true label, where we put another reference on\\nthe sock and a refcount underflow occurs.\\n\\nThis can happen for example if a handshake times out - particularly if\\nthe SUNRPC client sends the AUTH_TLS probe to the server but doesn\u0027t\\nfollow it up with the ClientHello due to a problem with tlshd.  When the\\ntimeout is hit on the server, the server will send a FIN, which triggers\\na cancellation request via xs_reset_transport().  When the timeout is\\nhit on the client, another cancellation request happens via\\nxs_tls_handshake_sync().\\n\\nAdd a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel\\npath so duplicate cancels can be detected.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\\n\\nnet/handshake: las cancelaciones duplicadas de handshake fugan el socket\\n\\nCuando una solicitud de handshake es cancelada, es eliminada de la lista handshake_net-\u0026gt;hn_requests, pero a\u00fan est\u00e1 presente en la handshake_rhashtbl hasta que es destruida.\\n\\nSi llega una segunda solicitud de cancelaci\u00f3n para la misma solicitud de handshake, entonces remove_pending() devolver\u00e1 falso... y asumiendo que HANDSHAKE_F_REQ_COMPLETED no est\u00e1 establecido en req-\u0026gt;hr_flags, continuaremos procesando a trav\u00e9s de la etiqueta out_true, donde ponemos otra referencia en el sock y ocurre un desbordamiento negativo del contador de referencias.\\n\\nEsto puede ocurrir por ejemplo si un handshake agota el tiempo de espera, particularmente si el cliente SUNRPC env\u00eda la sonda AUTH_TLS al servidor pero no la sigue con el ClientHello debido a un problema con tlshd. Cuando se alcanza el tiempo de espera en el servidor, el servidor enviar\u00e1 un FIN, lo que activa una solicitud de cancelaci\u00f3n a trav\u00e9s de xs_reset_transport(). Cuando se alcanza el tiempo de espera en el cliente, ocurre otra solicitud de cancelaci\u00f3n a trav\u00e9s de xs_tls_handshake_sync().\\n\\nA\u00f1adir un test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) en la ruta de cancelaci\u00f3n pendiente para que las cancelaciones duplicadas puedan ser detectadas.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/handshake/request.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\"lessThan\":\"011ae80c49d9bfa5b4336f8bd387cd25c7593663\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\"lessThan\":\"e1641177e7fb48a0a5a06658d4aab51da6656659\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\"lessThan\":\"3c330f1dee3cd92b57e19b9d21dc8ce5970b09be\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3b3009ea8abb713b022d94fba95ec270cf6e7eae\",\"lessThan\":\"15564bd67e2975002f2a8e9defee33e321d3183f\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/handshake/request.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.4\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.4\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.120\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.64\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.3\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.19\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-28T07:11:09+00:00",
      "cve": "CVE-2025-68775",
      "id": "CVE-2025-68775",
      "initial_release_date": "2025-01-01T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/handshake: duplicate handshake cancellations leak socket",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68775.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-25T00:24:28Z",
      "cve": "CVE-2025-68775",
      "id": "CVE-2025-68775",
      "initial_release_date": "2026-01-15T00:26:40Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "424",
      "product_status:known_not_affected": "200",
      "product_status:recommended": "402",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-68775",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-68775.json",
      "version": "35"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.


Detection rules are retrieved from Rulezet.