FKIE_CVE-2026-52947

Vulnerability from fkie_nvd - Published: 2026-06-24 17:17 - Updated: 2026-06-28 08:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove In qrtr_port_remove(), the socket reference count is decremented via __sock_put() before the port is removed from the qrtr_ports XArray and before the RCU grace period elapses. This breaks the fundamental RCU update paradigm. It exposes a race window where a concurrent RCU reader (such as qrtr_reset_ports() or qrtr_port_lookup()) can obtain a pointer to the socket from the XArray, and attempt to call sock_hold() on a socket whose reference count has already dropped to zero. This exact race condition was hit during syzkaller fuzzing, leading to the following refcount saturation warning and a potential Use-After-Free: refcount_t: saturated; leaking memory. WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0 Modules linked in: qrtr(+) bochs drm_shmem_helper ... Call Trace: <TASK> qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr] __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr] qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr] kernel_bind+0xe4/0x120 net/socket.c:3592 qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr] qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr] do_one_initcall+0xf5/0x5e0 init/main.c:1283 ... </TASK> Fix this by deferring the reference count decrement until after the xa_erase() and the synchronize_rcu() complete. (Note: The v1 of this patch incorrectly replaced __sock_put() with sock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove() still hold a reference to the socket, so freeing the socket memory here would lead to a subsequent UAF in the caller. Thus, the __sock_put() is kept, but only repositioned to close the RCU race.)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/03bfa95e452e2b6ccd76a332060ae4feaf5ad84d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2047c2aa0963bb2872fd722300a15bcb441a4c00
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2aa4c12723fe432e623462a3be42a197a128722b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3b20ec8f31e8a6a6782243f473b0abd3463621df
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/474293d90880622fde9d2430fb0165767090f7b3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7de2d447072be3b1a76793f034432338fc9c494b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a2171131ecda1ed61a594a1eb715e75fdad0fef5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ab269990ed58143a92a263be1bee626d82ac03da
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/qrtr/af_qrtr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2aa4c12723fe432e623462a3be42a197a128722b",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "03bfa95e452e2b6ccd76a332060ae4feaf5ad84d",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "474293d90880622fde9d2430fb0165767090f7b3",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "2047c2aa0963bb2872fd722300a15bcb441a4c00",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "7de2d447072be3b1a76793f034432338fc9c494b",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "ab269990ed58143a92a263be1bee626d82ac03da",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "3b20ec8f31e8a6a6782243f473b0abd3463621df",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            },
            {
              "lessThan": "a2171131ecda1ed61a594a1eb715e75fdad0fef5",
              "status": "affected",
              "version": "bdabad3e363d825ddf9679dd431cca0b2c30f881",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/qrtr/af_qrtr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.7"
            },
            {
              "lessThan": "4.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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\nnet: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove\n\nIn qrtr_port_remove(), the socket reference count is decremented via\n__sock_put() before the port is removed from the qrtr_ports XArray and\nbefore the RCU grace period elapses.\n\nThis breaks the fundamental RCU update paradigm. It exposes a race\nwindow where a concurrent RCU reader (such as qrtr_reset_ports() or\nqrtr_port_lookup()) can obtain a pointer to the socket from the XArray,\nand attempt to call sock_hold() on a socket whose reference count has\nalready dropped to zero.\n\nThis exact race condition was hit during syzkaller fuzzing, leading to\nthe following refcount saturation warning and a potential Use-After-Free:\n\n  refcount_t: saturated; leaking memory.\n  WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0\n  Modules linked in: qrtr(+) bochs drm_shmem_helper ...\n  Call Trace:\n   \u003cTASK\u003e\n   qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr]\n   __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr]\n   qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr]\n   kernel_bind+0xe4/0x120 net/socket.c:3592\n   qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr]\n   qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr]\n   do_one_initcall+0xf5/0x5e0 init/main.c:1283\n   ...\n   \u003c/TASK\u003e\n\nFix this by deferring the reference count decrement until after the\nxa_erase() and the synchronize_rcu() complete.\n\n(Note: The v1 of this patch incorrectly replaced __sock_put() with\nsock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove()\nstill hold a reference to the socket, so freeing the socket memory here\nwould lead to a subsequent UAF in the caller. Thus, the __sock_put() is\nkept, but only repositioned to close the RCU race.)"
    }
  ],
  "id": "CVE-2026-52947",
  "lastModified": "2026-06-28T08:16:25.587",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-24T17:17:04.760",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/03bfa95e452e2b6ccd76a332060ae4feaf5ad84d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2047c2aa0963bb2872fd722300a15bcb441a4c00"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2aa4c12723fe432e623462a3be42a197a128722b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3b20ec8f31e8a6a6782243f473b0abd3463621df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/474293d90880622fde9d2430fb0165767090f7b3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7de2d447072be3b1a76793f034432338fc9c494b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a2171131ecda1ed61a594a1eb715e75fdad0fef5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ab269990ed58143a92a263be1bee626d82ac03da"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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