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cuse: wait for pending RCU callbacks on module exit

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: cuse: wait for pending RCU callbacks on module exit Since commit 053fc4f755ad ("fuse: fix UAF in rcu pathwalks"), fuse_conn_put() frees the fuse_conn through call_rcu() rather than synchronously. For cuse, fc->release is cuse_fc_release(), which lives in the cuse module. If the module is removed before the RCU grace period ends, the callback jumps into freed module memory: userspace / module unload | RCU softirq ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ close(/dev/cuse) | cuse_channel_release() | fuse_dev_release() | fuse_conn_put(fch->conn) | call_rcu(delayed_release) ------+---> callback queued | rmmod cuse | cuse_exit() | cuse_channel_destroy() | ... | return | | | | rcu_do_batch() | delayed_release() | fc->release() | -> cuse_fc_release() | ^^^ freed text! The freed module text is unmapped by vfree(), so the jump into the stale callback triggers a page-fault Oops. If the virtual address is subsequently reused, the callback could execute unrelated code (undefined behaviour). Fix this by calling rcu_barrier() in cuse_exit() so that any pending fuse_conn release callback completes before the module is removed.

Announced Source revision 1
Original source ↗

CVE-2026-90140

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-90140

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "bfbab62ca69f72bcd14ea30de1fb98f6080ad464",
        "lessThan": "7fe415e1cd8fa875be263670c0ab47109818abb6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a8f650b93e55764ca9ff8e1ddebc151f57024086",
        "lessThan": "45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6",
        "lessThan": "ac5c499413385cea3e0220d6050408d50842891d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "053fc4f755ad43cf35210677bcba798ccdc48d0c",
        "lessThan": "a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "389bd349ddbcf90dbd8a4f2a4ab6e552d53df134",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "053fc4f755ad43cf35210677bcba798ccdc48d0c",
        "lessThan": "c40f3f24839f8404325a2099e26c2a04786ae309",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "053fc4f755ad43cf35210677bcba798ccdc48d0c",
        "lessThan": "4deb3edead0c0e172cc7349e8855d741d3c5e162",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "5.15.166",
        "lessThan": "5.15.221",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.107",
        "lessThan": "6.1.188",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.6.48",
        "lessThan": "6.6.157",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "fs/fuse/cuse.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.8",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/fuse/cuse.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-90140

Source reference: /cveMetadata/cveId

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No explicit severity was provided.

Event
#36539 · Revision 1
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