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locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: locking/rt: Fix the incorrect RCU protection in rt_spin_unlock() rt_spin_unlock() releases the RCU protection before unlocking the lock. That opens the door for the following UAF scenario: T1 T2 spin_lock(&p->lock); rcu_read_lock(); invalidate(p); p = rcu_dereference(ptr); rcu_assign_pointer(ptr, NULL); if (!p) return; spin_unlock(&p->lock); spin_lock(&p->lock) lock(&lock->lock); rcu_read_lock(); kfree_rcu(p); rcu_read_unlock(); .... spin_unlock(&p->lock) rcu_read_unlock(); // Ends grace period rcu_do_batch() kfree(p); UAF -> rt_mutex_cmpxchg_release(&lock->lock...) Regular spinlocks keep preemption disabled accross the unlock operation, which provides full RCU protection, but the RT substitution fails to resemble that. Same applies for the rwlock substitution. Move the rcu_read_unlock() invocation past the unlock operations to match the non-RT semantics. This makes it asymmetric vs. rt_xxx_lock(), but that's harmless as the caller needs to hold RCU read lock across the lock operation. The migrate_enable() call stays before the unlock operation because there is no per CPU operation in the unlock path which would require migration to be kept disabled.

Announced Source revision 1
Original source ↗

CVE-2026-72069

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-2026-72069

Linux

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

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

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": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "af28d801cd2db4cc7378554499bd4a5d84a5517e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "9d1fcd64ab81200e02b7a6db5eb1da8e244e8289",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "3cfaac77b3c32ac3940df28866de263c3f45d24c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "1f0d56d3f1e88f20f6e46109402f8c15d59bac37",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "633cadbc0b8323f5cc140a285d2432089dbb534e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "83f9fb561c1c3917e19f95523dd933c7d30291aa",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0f383b6dc96e976dfbf2721b0bf10bd96103b341",
        "lessThan": "89038cc87d80c77e7aa6f42a64b2573b74af339f",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "kernel/locking/spinlock_rt.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.15"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.15",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.217",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.184",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.148",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.101",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/locking/spinlock_rt.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72069

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#41859 · Revision 1
Added to Heist Feed
Publisher date
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