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