FKIE_CVE-2026-98688

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-19 10:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2f4cd43faa9d6470b30a9fbcbac6584db8108c1f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4310c6b8e75d6a47f7548e5948fbe6318aa4440a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/thunderbolt/tb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2f4cd43faa9d6470b30a9fbcbac6584db8108c1f",
              "status": "affected",
              "version": "a8937f35cf39c39c64325aa84d0463d866850857",
              "versionType": "git"
            },
            {
              "lessThan": "4310c6b8e75d6a47f7548e5948fbe6318aa4440a",
              "status": "affected",
              "version": "a8937f35cf39c39c64325aa84d0463d866850857",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3e9e823810b9a51f0bee9ed6e3d90df70484ff8d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9363cd4977260bf7f211feee54f85858bba2320c",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.266",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.217",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/thunderbolt/tb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "lessThan": "7.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "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\nthunderbolt: Fix NULL dereference in tb_remove_work()\n\nThere is a slight race between tb_remove_work() and tb_domain_remove()\nwhich leads to dereferencing a NULL tb-\u003eroot_switch pointer inside\ntb_free_unplugged_xdomains():\n\n        Thread A                            Thread B\n\n  tb_remove_work()\n                                    tb_domain_remove()\n                                      mutex_lock(\u0026tb-\u003elock)\n                                      tb_stop()\n                                        /* doesn\u0027t cancel a running callback */\n                                        cancel_delayed_work(\u0026tcm-\u003eremove_work)\n                                        ...\n                                        tb_switch_remove(tb-\u003eroot_switch)\n                                        tb-\u003eroot_switch = NULL\n                                      mutex_unlock(\u0026tb-\u003elock)\n    mutex_lock(\u0026tb-\u003elock)\n    ...\n    /* without checking -\u003eroot_switch */\n    tb_free_unplugged_xdomains(tb-\u003eroot_switch)\n    mutex_unlock(\u0026tb-\u003elock)\n\nCommit a8937f35cf39 (\"thunderbolt: Remove XDomain from the bus without\nholding tb-\u003elock\") doesn\u0027t seem right to move tb_free_unplugged_xdomains()\nout of the \u0026tb-\u003elock section and the check for tb-\u003eroot_switch, in\nparticular.  It states:\n\n  For this reason separate removing the XDomain from the topology data\n  structures (where we need the lock) from unregistering the device from\n  the bus (where remove callbacks of the drivers are being called).\n\ntb_free_unplugged_xdomains() belongs to the former group of functions\nrequiring the lock.  And it also calls tb_xdomain_remove() which should\nonly be called with \u0026tb-\u003elock held.\n\nFound by Linux Verification Center (linuxtesting.org) with Svace static\nanalysis tool."
    }
  ],
  "id": "CVE-2026-98688",
  "lastModified": "2026-10-19T10:19:33.190",
  "metrics": {},
  "published": "2026-10-18T16:17:22.207",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2f4cd43faa9d6470b30a9fbcbac6584db8108c1f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4310c6b8e75d6a47f7548e5948fbe6318aa4440a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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