FKIE_CVE-2026-72221

Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-17 06:18
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sunrpc: wait for in-flight TLS handshake callback when cancel loses race When wait_for_completion_interruptible_timeout() in svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and tls_handshake_cancel() then returns false, handshake_complete() has won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and is about to invoke svc_tcp_handshake_done(), but the callback's side effects on xpt_flags and on svsk->sk_handshake_done have not yet committed. The current code reads xpt_flags immediately to decide whether the session succeeded. Two races result. If the callback has executed set_bit(XPT_TLS_SESSION) but not yet clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session, enqueues the transport, and returns. svc_xprt_received() then clears XPT_BUSY, a worker thread picks the transport up, the dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set, and xpo_handshake is invoked a second time. That svc_tcp_handshake() calls init_completion(&svsk->sk_handshake_done) while the original callback concurrently calls complete_all() on it, corrupting the embedded swait_queue. If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet entered svc_tcp_handshake_done(), svc_tcp_handshake() reads XPT_TLS_SESSION as clear and tears the connection down even though the handshake is about to succeed. Wait for the callback to commit before inspecting xpt_flags. The completion is guaranteed to fire because handshake_complete() invokes svc_tcp_handshake_done() unconditionally once it has set HANDSHAKE_F_REQ_COMPLETED.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sunrpc/svcsock.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9",
              "status": "affected",
              "version": "b3cbf98e2fdf3cb147a95161560cd25987284330",
              "versionType": "git"
            },
            {
              "lessThan": "e0f4691d42a54d359d8b64509fd9ab938d4f2a33",
              "status": "affected",
              "version": "b3cbf98e2fdf3cb147a95161560cd25987284330",
              "versionType": "git"
            },
            {
              "lessThan": "65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b",
              "status": "affected",
              "version": "b3cbf98e2fdf3cb147a95161560cd25987284330",
              "versionType": "git"
            },
            {
              "lessThan": "a4f878e8ecd729ccf2e50993444e217583adeace",
              "status": "affected",
              "version": "b3cbf98e2fdf3cb147a95161560cd25987284330",
              "versionType": "git"
            },
            {
              "lessThan": "d00e32f84ca1a77cb67a3fbf59f58dada95f5a21",
              "status": "affected",
              "version": "b3cbf98e2fdf3cb147a95161560cd25987284330",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sunrpc/svcsock.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": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nsunrpc: wait for in-flight TLS handshake callback when cancel loses race\n\nWhen wait_for_completion_interruptible_timeout() in\nsvc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and\ntls_handshake_cancel() then returns false, handshake_complete() has\nwon the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and\nis about to invoke svc_tcp_handshake_done(), but the callback\u0027s\nside effects on xpt_flags and on svsk-\u003esk_handshake_done have not\nyet committed.\n\nThe current code reads xpt_flags immediately to decide whether the\nsession succeeded. Two races result.\n\nIf the callback has executed set_bit(XPT_TLS_SESSION) but not yet\nclear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session,\nenqueues the transport, and returns. svc_xprt_received() then\nclears XPT_BUSY, a worker thread picks the transport up, the\ndispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set,\nand xpo_handshake is invoked a second time. That svc_tcp_handshake()\ncalls init_completion(\u0026svsk-\u003esk_handshake_done) while the original\ncallback concurrently calls complete_all() on it, corrupting the\nembedded swait_queue.\n\nIf the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet\nentered svc_tcp_handshake_done(), svc_tcp_handshake() reads\nXPT_TLS_SESSION as clear and tears the connection down even though\nthe handshake is about to succeed.\n\nWait for the callback to commit before inspecting xpt_flags. The\ncompletion is guaranteed to fire because handshake_complete()\ninvokes svc_tcp_handshake_done() unconditionally once it has set\nHANDSHAKE_F_REQ_COMPLETED."
    }
  ],
  "id": "CVE-2026-72221",
  "lastModified": "2026-08-17T06:18:23.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:21:40.990",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a4f878e8ecd729ccf2e50993444e217583adeace"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d00e32f84ca1a77cb67a3fbf59f58dada95f5a21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e0f4691d42a54d359d8b64509fd9ab938d4f2a33"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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